Magic Bars

INGREDIENTS

• 2 tablespoons instant espresso powder
• 1 1/4 cups chopped walnuts
• 1 1/3 cups all-purpose flour
• 1 large egg, at room temperature
• 3 large eggs, at room temperature
• 1/2 teaspoon baking powder
• 1/4 teaspoon fine sea salt
• 1 stick (1/2 cup) unsalted butter, cut into 1/2-inch pieces, at room temperature
• 1/2 cup vegetable oil
• 1 tablespoon pure vanilla extract
• One 21-ounce box brownie mix, such as Duncan Hines Chewy Fudge
• Caramels, unwrapped
• 3/4 cup sweetened shredded coconut
• 1/2 cup semisweet chocolate chips
• 1 teaspoon pure vanilla extract
• 1/2 teaspoon baking soda
• 3/4 cup packed light brown sugar
• 1/2 cup granulated sugar
• Vegetable-oil cooking spray
• Three 9.5-ounce bags soft caramel candies (about 90 caramels), such as Kraft Classic