I had to look it up. “Sur lie” is a French phrase that describes aging wine “on the lees” – the rich sediment that accumulates during fermentation. Vintners use what lies below to enhance the flavor of their wine and render a more complex, nuanced vintage.

At Sur Lie restaurant in Portland, chef Emil Rivera is practicing a similar kind of alchemy. He takes morsels of meat or fish and enhances their flavor by floating them on a concentrated sauce, a creamy puree or an ethereal cloud of foam. The website may call Sur Lie a “tapas-style restaurant,” but it’s not a place for predictable, bite-sized Spanish snacks. The food here is more varied and more inventive; Rivera calls it “global cuisine.” Co-owned by Krista Cole and Antonio Alviar, Sur Lie serves “shareable plates” – bigger than typical restaurant appetizers, but not as generous as entrees.

You can start with a selection of cheeses and charcuterie or dive right into these shareable plates, which are organized into three categories: “Crisp,” “Pleasant” and “Bold,” roughly translating to light, medium and heavy. Our waitress suggested that we plan on three to four plates per person, which is about right if you include dessert. The portion sizes seem diminutive at first, but don’t worry about leaving hungry; you’re encouraged to keep sharing and ordering throughout the meal.

Before the food arrives, you’re welcomed with a shot glass of sparkling soda – blood orange with cranberry the night we visited. It’s a good indication of what’s to follow: a small serving, but one with bold flavor.

Take the Poached Haddock ($8) on the “Crisp” menu, a moist piece of a fillet, served atop a parsnip puree with a dribble of salsa verde on the side. The simply cooked fish is good, but the puree is delicious, an earthy, salty and velvety complement – and a clear demonstration that what lies beneath is not merely a supporting player, it’s a full-fledged co-star.

I thought the same thing about the jam-like confit of caramelized onions under the hanger steak ($12) (sourced locally from Archer Angus Farm in Chesterville.) Once again, the steak was nicely prepared (the kitchen sears the beef and presents slices medium rare), but the sauce underneath was a standout: rich and sweet and sour all at the same time, thanks to slow-cooked onions, sherry vinegar and an unexpected addition that I had to ask about – house-made mustard butter. Chef Rivera calls his hanger steak “a refined version” of the steak and onions he ate as a child in Puerto Rico. He was one lucky kid.

“As a chef, I like to work on flavor layering and reinforcement,” Rivera says, “a layer of flavor reinforced with a different texture or taste.” It’s an approach he cultivated in Washington, D.C., while working for renowned chef José Andrés. “One important thing that I learned there was respect for technique. If you don’t know how to poach and sauté properly, you’ll lose the essence of good food. We use our sauces and modernist foams here to add something special instead of just being a gimmick.”

The Yukon Gold potato foam that he serves with pork cheeks ($11) definitely adds something special. In fact, it makes the dish. The foam is buttery and herbal (the spuds are cooked with sage), but instead of coating your tongue like a forkful of whipped potato, it evaporates in a cloud of bubbles, allowing you to focus exclusively on the super-rich pork cheeks. I loved this “Bold” entree, not just because of that evanescent foam (I kept reaching for more to savor the disappearing act), but also because the pork was so flavorful. Braised with onions and apples, the meat was fall-apart tender and deeply satisfying, especially with a spoonful of the braising jus on top. Translucent shavings of pickled apples provided another layer of flavor and a bright, tart finish.

Rivera says that virtually every dish on the menu at Sur Lie is an homage to a person or a style of cooking, and the Brussels sprouts ($8) are his tribute to Spanish cuisine. (They’re also further proof of his passion for layered flavors and textures.) The roasted sprouts are mixed with smoky-sweet pimenton, meaty pork lardons and Marcona almonds. I liked them well enough when I took my first bite, but found that the flavors kept deepening and changing each time I returned to the plate – saltiness, for example, receded, while the earthiness of the paprika strengthened. These Brussels sprouts are like maddeningly good school snacks for grownups. You may have to use a napkin (the paprika will stain your fingers) but you just want to put down your lunch box, kick off your sneakers and down a few more.

Several friends who frequent Sur Lie (and more than a few bloggers and online reviewers) rave about the Sweet Pea Hummus ($7) , but I was less than wowed. The color is striking – a vivid green straight off of a Pantone chip – and I liked how mint oil enlivened the silky spread, but the sugary lemon sabayon on the side overwhelmed the delicate pea flavor. I preferred the hummus solo, spread on the crunchy lavash that the waitress brought to the table. Two layers were plenty.

A better and more balanced bet for those craving something sweet is the oatmeal pudding dessert ($6), Rivera’s tribute to his maternal grandmother. Topped with a scattering of macerated cranberries and a caramelized glaze, it’s colorful and aromatic (I could smell cinnamon, cardamom and vanilla rising off the cast-iron serving dish), and the Maine Grains Cracked Oats are intensely sugary and creamy. I chased the final bites around a near-empty skillet.

It’s still early days for Sur Lie, which opened last summer. The owners say that the menu will change with the seasons and continue to spotlight local ingredients and local purveyors. (At least one dessert always features ice cream from Catbird Creamery in Westbrook.) And Rivera plans to continue experimenting with what he calls “modern interpretations of classic food.” But underneath it all, Sur Lie is onto something. Trying a single, familiar dish is fun. Sharing a selection of creative, inventive dishes is even better.

James H. Schwartz has covered food, travel and architecture for The Washington Post, Down East, Coastal Living and Southern Living magazines for more than 30 years. Long a commuter between Portland and Washington, D.C., he retired from his job as vice president at the National Trust for Historic Preservation in 2013 and relocated to Maine.