Caramel Apple "Payday" Bars

Line a 9x13-inch baking dish with parchment, coat with cooking spray, then evenly spread diced apples in the bottom.

Place butter and cream in a microwaveable container with pouring spout. Microwave until butter is fully melted, 1 to 3 minutes, and set aside. In a saucepan, combine sugar, corn syrup, and water. Stir until sugar is moistened and uniform. Heat over medium until the mixture begins to boil. Stir once, then cover with lid for 1 minute to melt any sugar from the sides of the pan. Continue to boil uncovered WITHOUT STIRRING for 6 to 12 minutes, until mixture reaches 240 F on a candy thermometer, then turn off heat. Slowly pour the cream/butter mixture into the sugar mixture a little at a time, whisking to incorporate. (It will boil intensely at this stage.)

Turn heat to medium-high. Continue boiling WITHOUT STIRRING until mixture reaches 240 F again, about 10 minutes. Remove from heat and whisk in vanilla and salt. Pour caramel over top of the apple layer and smooth out surface with a spatula. Evenly spread peanuts over caramel and lightly press peanuts into caramel with your hand. Let cool uncovered overnight. Transfer bars to a flat surface by lifting edges of parchment paper. Peel paper off sides and cut into squares with a sharp knife. Store in an airtight container at room temperature for up to a week.