For the Brownie Layer:
1 (18 ounce) package fudge brownie mix (such as Duncan Hines®)
½ cup vegetable oil
¼ cup water
For the Pecan Pie Layer:
½ cup brown sugar
⅓ cup light corn syrup
2 large eggs
1 tablespoon bourbon (Optional)
2 teaspoons vanilla extract
½ teaspoon sea salt
¼ cup unsalted butter, melted and cooled slightly
2 cups pecan halves
Preheat the oven to 350 degrees F (175 degrees C). Line a deep 9-inch springform pan with aluminum foil and coat generously with cooking spray.
Whisk brownie mix, oil, 2 eggs, and water together in a bowl until well combined. Spread batter into the prepared pan.
Bake in the preheated oven until a toothpick inserted into center comes out clean, about 30 minutes. Remove from the oven and leave the oven on.
Whisk brown sugar, corn syrup, 2 eggs, bourbon, vanilla extract, and salt together in a bowl. Add melted butter slowly, whisking until well combined. Add pecans and stir to coat in filling. Pour gently over brownie layer; spread evenly using a spatula.
Bake in the hot oven until center is set, 30 to 35 minutes. Let cool to room temperature at least 2 hours.
Honey can be used in place of corn syrup.
You can use light or dark brown sugar.
If desired, chill the final product in the fridge for a shorter cooling time.