This is a recipe with a million uses! Undercook it just a bit and you’ll have an incredible caramel sauce; overcook it a hair and you’ll end up with a rigid glue that will hold together some of the strangest structures. My only warning is to use extreme caution when working with caramel, as it’s incredibly hot and sticky. I would avoid involving children or anyone else lacking in common sense when executing this recipe.
Makes one 13 x 18-inch sheet
1 cup (2 sticks) unsalted butter, softened, plus more for pan
2 cups granulated sugar
1 cup packed light brown sugar
1 cup whole milk
1 cup heavy whipping cream
1 cup light corn syrup
1 teaspoon vanilla extract
1 teaspoon coarse salt (optional)
• Generously butter a 13 x 18–inch baking pan. Combine sugars, butter, milk, cream, and corn syrup in a heavy saucepan over medium-low heat and stir until sugars are dissolved. Heat slowly until mixture comes to a boil, stirring frequently. Clip a candy thermometer to inside of pot and heat and continue to stir until it registers 245°F (see Note). Immediately remove pot from heat, add vanilla, and stir vigorously.
• Quickly pour caramel into prepared baking pan and allow to cool. Sprinkle with coarse salt, if you like.
NOTE: For a caramel sauce, heat just to 230°F before removing from heat and adding vanilla.