On a particularly hectic day recently, as I fell dead tired into bed, I noticed a nearly full mug of coffee sitting on my nightstand. “Oh, that’s where I left it,” I remembered, mumbling something about being less wasteful tomorrow as I dropped off to sleep.

When I woke up, the internet proffered a statistic that jolted me harder than my typical caffeine infusion does. According to United Nations Food and Agricultural Organization figures, it takes about 37 gallons of fresh water to grow, process and transport enough beans to make a single cup of coffee. Forgetting where I left my coffee the day before was like running the tap full tilt for over 10 minutes and letting the water run down the drain.

That water footprints number has been bouncing around the internet since the UN designated 2005 to 2015 the ‘Water for Life’ decade to raise awareness about millions of people, most of them children, dying from diseases associated with inadequate water supply, sanitation and hygiene while tens of millions of others were taking their clean water supply for granted.

To be fair to the coffee industry, coffee growers, processors, sellers and servers assert (and ecolabels like The Rainforest Alliance certify) that a number of water conservation efforts have lowered coffee’s water footprint; these efforts include growing coffee cherries in the shade, repurposing the pulp left over from the water-intensive processing of coffee cherries to beans, huge companies like Starbucks reducing water consumption by as much as 25 percent, and institutional dining services recycling coffee grounds for compost and bio-fuel. But the number has certainly not been reduced to zero, so if you’re going to drink coffee, make sure you don’t waste the money, sweat and water that went into that cup of joe.

Before I offer my waste-not, want-not coffee tips and tricks, though, I need to come clean about the fact that I am not a super fussy coffee drinker. We buy Green Mountain Coffee Roasters’ or Dunkin Donuts’ blends on sale at Shaw’s, brew just one pot a day in our $30 drip machine and prefer a cuppa tea in the afternoon. If you are a coffee aficionado who can see the difference between a medium grind and medium-coarse grind and measures the water down to the milliliter, you might prefer the accompanying Alison McConnell story on how coffee shops compost their grinds after brewing perfect cups.

Let’s start with that half cup of brewed coffee in the pot that never got drunk this morning. My first suggestion is to pair it with chocolate. Chocolate and coffee have a similar flavor profile: loud and bitter, in a good way, of course. When you add some coffee to a recipe with lots of other ingredients like, say, a chocolate cake, you intensify those rich flavors without making the finished product taste like coffee. This flavor elevation can happen whether you’re making your grandmother’s triple layer cake or a box of Duncan Hines brownies. Simply substitute coffee for the water called for in the recipe. Just be sure to add the coffee at the temperature the recipe specifies. Adding cold coffee to Swiss Miss Cocoa mix is a bad idea, while adding hot coffee to a yeasted chocolate dough might kill the yeast.

My go-to savory coffee combination entails smoked chipotle chili peppers, both when they are steeped in adobo sauce in cans found in the Mexican food section of the grocery store or ground into a powder and found in the spice aisle. I’ve been making twice-baked sweet potatoes with chipotle and lime since Fine Cooking published the recipe 10 years ago. When I stir in the minced chipotle in adobo, I also stir in a tablespoon of strong coffee. When I make beef chili, after I’ve browned the beef, but before I stir in the chili powder, I deglaze the pan with a half cup of coffee.

You don’t have to make chocolate cake or chili as soon as you find that last half cup in the pot. Pour it into an ice cube tray (preferably one that has a sealed lid as coffee will pick up odors from other foods in the freezer) and freeze it.

Many modern baking recipes call for espresso powder, a specialty ingredient that you stir into warm water before adding it to the batter. Because espresso is roasted, ground and brewed differently, it has a richer coffee flavor. To get a close approximation for this espresso powder/water combination from your frozen stash of leftover coffee, double the volume of water called for in the recipe and place that volume of ice cubes (the standard ice cube comprises 2 tablespoons) in a measuring cup. When the cubes melt halfway, scoop out the still frozen parts (which will be primarily water) and you’ll be left with concentrated coffee.

The best culinary use I know for spent coffee grounds is to use them to flavor milk or cream, because those ingredients are typically held at a cool temperature. Adding a second dose of heat to the grounds (the first one being when you brewed your coffee) tends to bring out an unpleasant acidity. Say I’m making instant Jell-O pudding for a chocolate pie (don’t judge people, sometimes I simply don’t want to spend my local egg yolks in a pie), I’ll put my morning coffee grounds in a jar with some milk and let the mixture steep in the fridge for couple of hours before making the pudding. If I’m craving coffee ice cream, about the same time I put the ice cream maker canister in the freezer (it takes 24 hours to freeze properly) I mix my morning grounds with heavy cream to start building the flavor in the ice cream’s base. The ratio here should be 1/4 cup spent coffee grounds to 2 cups of milk or cream.

Cleanly straining the grounds from the milk and cream is crucial to the finished product. A typical kitchen strainer will let many of the grounds through. For best results, employ a French press coffee pot or a fine mesh or metal tea strainer. It’s also best, from a food safety standpoint, to use your spent grounds while they are still hot. Coffee grounds left at room temperature all day can be a breeding ground for bacteria.

Other uses for coffee milk include adding a bit of caffeine (spent grounds only give you about 25 percent of the caffeine you get from the primary brew) to your morning oatmeal, making killer coffee milkshakes and upping your sweet bread pudding game. Whip coffee cream to top chocolate desserts, use it to make mocha buttercream frosting, or use it as a base for panna cotta or crème brûlée. All of these are great options considering you used to routinely throw your coffee grounds into the compost bin. By the way, you can still do that after they’ve been used twice.

Christine Burns Rudalevige is a food writer, recipe developer, tester and cooking teacher in Brunswick, and the author of “Green Plate Special,” a cookbook from Islandport Press based on these columns. She can be contacted at: cburns1227@gmail.com.

Triple Decker, Coffee-Infused Chocolate Cake

Stella Parks’ Devil’s Food Cake has been my go-to decadent dessert recipe ever since I tested it before she published it in her “Brave Tart: Iconic American Desserts” cookbook. After all, each layer requires a stick of butter, and 2 whole eggs and an extra yolk. And that’s before you make my mocha-flavored buttercream to frost. Slice the pieces small and share this cake with all your friends. Flex your sustainability muscle by letting them know you made it with leftover coffee.

Serves 12, at least

1½ cups (3 sticks or 12 ounces) unsalted butter, more for greasing the pans
1½ cups brewed black coffee
1 cup (3 ounces) Dutch-process cocoa powder
1¼ cups (6 ounces) finely chopped dark chocolate
2 cups (16 ounces) light brown sugar
1 tablespoon vanilla extract
1 teaspoon kosher salt
6 large eggs, straight from the fridge
3 large egg yolks, straight from the fridge
2 cups (9 ounces) all-purpose flour
1 tablespoon baking soda
4 cups mocha buttercream frosting, recipe follows

Adjust the oven rack to the lower-middle position and preheat the oven to 350 degrees. Coat three (8-inch round) cake pans with butter and line their bottoms with fitted rounds of parchment paper.

Combine butter and coffee in a 5-quart stainless steel pot over low heat. Once the butter has melted, remove the mixture from the heat, mix in the cocoa and chocolate and then stir in the brown sugar, vanilla and salt. Mix in the whole eggs and yolks, and then sift in the flour and baking soda. Whisk thoroughly to combine.

Divide the batter among the prepared cake pans and bake until the cakes are firm, but your finger can still leave an impression in the puffy crust, about 30 minutes (a toothpick inserted into the center should come away with a few crumbs still attached).

Cool cakes directly in their pans for 1 hour, then run a butter knife around the edges to loosen. Invert onto a wire rack, peel off the parchment, and return cakes right side up. Meanwhile, prepare the frosting.

Level the cakes with a serrated knife and set any scraps aside for snacking. Place 1 layer on a plate (or a cake turntable if you have one). Top with 1 cup buttercream, using an offset spatula to spread it evenly from edge to edge. Repeat with second and third layers, then cover the sides of the cake with another cup of buttercream, spreading it as smoothly as you can.

Under a cake dome or an inverted pot, the frosted cake will keep 24 hours at cool room temperature. After cutting, wrap leftover slices individually and store at cool room temperature up to 3 days more.

Mocha Buttercream Frosting

Making the coffee-flavored cream called for here is simple. Combine 2 cups heavy cream and ¼ cup spent coffee grounds in a mason jar. Refrigerate for 4 to 24 hours. Strain well.

Makes a generous 4 cups

6 cups powdered sugar
3 tablespoons Dutch-process cocoa powder
1½ cups (3 sticks) unsalted butter, softened
1 tablespoon strong coffee
3 tablespoons coffee-flavored heavy cream

Sift together the powdered sugar and cocoa and set aside.

Place the butter in a stand mixer fitted with a paddle attachment. Beat the butter on low until it’s smooth. Scrape down the sides of the bowl with a spatula. Beat the butter on high until its light and creamy, 3-4 minutes. Scrape down the bowl.

Add 1½ cups of the combined sugar-cocoa mixture and the coffee. Mix on low until combined. Scrape down the sides, and add another 1½ cups of sugar-cocoa mixture and 1 tablespoon of the coffee-flavored cream. Repeat that process twice more until all the sugar-cocoa mixture and the cream are incorporated. Scrape down the sides once more and beat the frosting on high for 1 minute. Frost your cake.

Coffee Ice Cream

This recipe is adapted from the basic vanilla ice cream recipe in David Lebovitz’s book “The Perfect Scoop” from Ten Speed Press.

Makes 1 quart

2 cups heavy cream
1/4 cup spent coffee grounds
1 cup whole milk
Pinch of salt
3/4 cup sugar
5 large egg yolks

Combine the cream and coffee grounds in a mason jar. Refrigerate for 4 to 24 hours. Strain well.  Compost the grounds. Set up an ice bath by placing a 2-quart bowl in a larger bowl partially filled with ice and water. Set a strainer over the top of the smaller bowl and pour the coffee flavored cream into the bowl.

Heat the milk, salt and sugar in a saucepan, stirring so that the sugar dissolves.

In a measuring cup, whisk egg yolks. To temper the yolks, gradually pour some of the warm milk into the yolks, whisking constantly as you pour. Scrape the warmed yolks and milk back into the saucepan.

Cook over low heat, stirring constantly and scraping the bottom with a heat-resistant spatula until the custard thickens enough to coat the spatula. Strain the custard to remove any scrambled egg bits into the heavy cream. Stir over the ice until cool and then refrigerate to chill thoroughly. Preferably overnight.

Freeze the custard in your ice cream maker according to the manufacturer’s instructions.