The key ingredient in caramel may be sugar, but this classic dessert sauce is much more than just sweet: It has an irresistibly nutty, buttery, bittersweet flavor. Caramel gets its complexity from a process appropriately known as caramelization: When sugar is heated to high enough temperatures, it undergoes an array of chemical reactions that create new flavor compounds. For our classic caramel, we made our recipe foolproof by adding water to ensure that the sugar fully dissolved, avoiding the common pitfalls of burning and crystallization (which occur when the sugar cooks unevenly). This method lent itself nicely to flavor variations, like our Caramel-Chocolate-Pecan Sauce.

Makes about 1½ cups

We prefer an instant-read thermometer for measuring the temperature of caramel. To ensure an accurate reading, swirl the caramel to even out hot spots, then tilt the pot so that the caramel pools 1 to 2 inches deep. Move the thermometer back and forth for about 5 seconds before taking a reading.

1 cup (7 ounces) sugar
⅓ cup water
3 tablespoons light corn syrup
¾ cup heavy cream
2 ounces bittersweet chocolate, chopped
1 tablespoon unsalted butter, chilled
½ cup pecans, toasted and chopped
1 teaspoon vanilla extract
⅛ teaspoon salt

1. Bring sugar, water, and corn syrup to boil in large saucepan over medium-high heat. Cook, without stirring, until mixture is straw-colored, 6 to 8 minutes. Reduce heat to low and continue to cook, swirling saucepan occasionally, until caramel is amber-colored, 2 to 5 minutes. (Caramel will register between 360 and 370 degrees.)

2. Off heat, carefully stir in cream; mixture will bubble and steam. Stir in chocolate and butter and let sit for 3 minutes. Whisk sauce until smooth and chocolate is fully melted. Stir in pecans, vanilla, and salt. Let cool slightly. (Sauce can be refrigerated for up to 2 weeks; gently warm in microwave, stirring every 10 seconds, until pourable, before using.)

What better way to showcase our Caramel-Chocolate-Pecan Sauce than in a decadent turtle pie? Recipes for this indulgent dessert vary quite a bit, so we first needed to figure out what we wanted from each element. We opted for a cookie-crumb crust made with chocolate wafer cookies, which had a pleasant mild sweetness that contrasted with the sweet sauce. Many recipes save the caramel sauce for the topping only, but tasters thought this seemed like an afterthought. We preferred the sauce to be more integrated into the pie, so we decided to put a generous layer right on the baked crust. We then topped it off with a filling made with marshmallow crème, cream cheese, heavy cream, peanut butter, and butter. The cream cheese tempered the sweetness of the marshmallow crème, while the heavy cream helped to make the filling fluffy and light, rather than sticky and gooey. Drizzling some additional sauce on top of the pie gave it an appealing finish and drove the turtle flavor home.

Serves 8 to 10

The sauce will need to be warm so that it is pourable. We developed this recipe with Fluff brand marshmallow crème, but any brand of marshmallow crème will work; do not use products labeled marshmallow sauce or marshmallow topping. When working with the marshmallow crème, grease both the inside of your measuring cup and a spatula with vegetable oil spray to prevent sticking.

CRUST
25 chocolate wafer cookies (5½ ounces), broken into coarse pieces
4 tablespoons unsalted butter, melted

FILLING
1 recipe Caramel-Chocolate-Pecan Sauce (see above)
8 ounces cream cheese, softened 1 cup marshmallow crème
½ cup heavy cream
½ cup creamy peanut butter
2 tablespoons unsalted butter, softened

1. FOR THE CRUST: Adjust oven rack to middle position and heat oven to 325 degrees. Process cookie pieces in food processor until finely ground, about 30 seconds. Add melted butter and pulse until combined, about 6 pulses. Sprinkle mixture into 9‐inch pie plate. Using  at bottom of dry measuring cup, press crumbs firmly into even layer on bottom and sides of pie plate. Bake until crust is fragrant and set, about 15 minutes. Transfer to wire rack and let cool slightly.

2. FOR THE FILLING: Pour 1 cup of sauce into bottom of cooled crust and refrigerate, uncovered, until set, about 30 minutes.

3. Using stand mixer fitted with paddle, beat cream cheese, marshmallow crème, heavy cream, peanut butter, and butter on medium‐high speed until light and fluffy, about 5 minutes, scraping down sides of bowl as needed. Spread filling evenly into crust. Cover pie and refrigerate until filling is chilled and set, at least 2 hours or up to 1 day. Drizzle remaining sauce attractively over top of pie and serve.