BRUNSWICK — The recipe cards, torn and stained, stay by Eileen Hornor’s side as she crushes graham crackers to make the crust for her favorite cheesecake.

She doesn’t need them. She’s made this cheesecake so many times she knows it by heart. But the cards, which date back to the 1960s, are in her mother Helen’s handwriting, and her daughter – also named Helen – scribbled on them when she was a toddler.

“It’s a very precious thing to me because I still have the index cards of my mother’s handwriting, and I don’t have a lot from her,” Hornor said in the kitchen of The Brunswick Inn, which she has owned for seven years. “She died 20 years ago.”

So why is this luscious dessert, which has become not only a family favorite but also one of the most-requested desserts at the inn, called “Sister Marion’s Cheesecake”? The recipe was given to the family by a nun in New York – which, it turns out, is a whole other story.

Sister Marian Keane (her first name is spelled with an “a,” despite what’s written on the recipe card) taught Hornor’s six older siblings in elementary school. Hornor’s father, a New Yorker who knew good cheesecake when he tasted it, was active in the parish council.

“At a parish council dinner at the local convent, Sister Marian served this cheesecake,” Hornor said. “My older sister remembers my father coming home and saying to my mother ‘Helen, you’ve got to call Sister Marian and get that recipe. This is the best thing I’ve ever tasted.’ ”

She did and the cheesecake soon became a family tradition. Hornor’s mother made it for every Easter, Thanksgiving and Christmas celebration. This year, Hornor made one to take to her sister’s house in Massachusetts for Thanksgiving. Hornor likes the recipe for its simplicity. Although her mother’s index cards list several suggestions for toppings, including strawberries, cherry pie filling and fresh pineapple, she always uses a simple sour cream topping. It’s cheesecake, Hornor says, before cheesecake “got destroyed.”

“I’m not saying that pumpkin cheesecake is always bad, or chocolate cheesecake is always bad, but I happen to be a bit of a purist, and I prefer things in their simplicity,” she said.

The recipe is quick and easy, but does have its quirks. It calls for beating the egg whites and folding them into the cream cheese, only then adding the yolks, “which is totally counterintuitive,” Hornor said.

The cheesecake, topped with slivered almonds and a dusting of cinnamon, is dense and rich – even sinful, although Sister Marian might not care for that description.

Who was Sister Marian? Hornor is too young to have a lot of personal memories of her, but does recall her being a cheerful “big woman with giant black orthotic shoes.”

“She was this kind, pudgy lady in a sea of mean, angular nuns,” Hornor recalled, laughing.

What ever happened to her? An email to St. Andrew Avellino Roman Catholic Church in Flushing, New York, revealed that she was a member of the Dominican Sisters of Columbus Ohio, and that she died about six years ago.

A little Googling filled in the rest of her story. Sister Marian was born in New Haven, Connecticut, and entered the Dominican Sisters of St. Mary of the Springs (now known as the Sisters of Peace) in Columbus, Ohio, in 1945, at age 37. She took her vows two years later. She had a bachelor’s degree in education, and taught in Catholic schools in Ohio, Pennsylvania and New York. She was at St. Andrew Avellino, where Hornor’s family met her, from 1969 until 1981. After retiring from teaching, she spent the rest of her life doing community service at the church and ministering at a local nursing home. Among other post-retirement activities, she taught remedial reading and coordinated the church’s efforts to care for the homeless. She died in 2009 at age 100 in Columbus.

There are even a couple of photos of her on the internet, Including one of her 100th birthday party, where she is surrounded by 100 pink roses and photos from her long life. In the photo, she is blowing kisses. She must have smiled a lot that day, but then again, Hornor remembers her as a woman who was always smiling.

“Because if you eat this cheesecake,” she said, “you’re happy all the time.”

SISTER MARION’S CHEESECAKE

Yes, it seems odd to beat the egg whites to peaks, then beat in the sugar and yolk after, but that’s how Sister Marian made it – you wouldn’t doubt a nun, would you?

Serves 8-10

FOR THE CRUST:

20 graham cracker squares

4 tablespoons butter, melted

1/4 cup sugar

Preheat the oven to 350 degrees F. Put the crackers into a sealed bag and roll them into crumbs with a rolling pin. Combine the crumbs with the butter and sugar and press the mixture into the bottom of a 9-inch springform pan. Bake for 5 minutes.

FOR THE FILLING:

3 eggs, separated

2 (8-ounce) packages cream cheese, softened

1/2 cup sugar

Meanwhile, beat the egg whites until they form stiff – but not dry – peaks. Set aside. In a separate bowl, beat the cream cheese until fluffy. Fold in the beaten egg whites. Beat in the sugar and the yolks until the batter is smooth. Pour the batter onto the prebaked crust and bake for 25 to 30 minutes until set. Cool 20 minutes.

FOR THE TOPPING:

1 (12-ounce) carton sour cream

1 cup sugar

1 teaspoon vanilla extract

Ground cinnamon

Slivered almonds

Combine the sour cream with the sugar and vanilla and gently spoon the mixture over the cheesecake. Sprinkle with cinnamon and almonds and bake for 10 minutes. Cool the cheesecake to room temperature. Chill in the refrigerator at least 6 hours. The flavor improves after 12 to 24 hours.