S'mores Brownie Bars Recipe

Ingredients (11)

• 1 cup graham cracker crumbs (made from 10 rectangular crackers)
• 12 tablespoons (1 1/2 sticks) unsalted butter
• 1/2 cup plus 1 tablespoon sugar
• Salt
• 1 cup bittersweet chocolate chips
• 2 large eggs, at room temperature
• 1 teaspoon instant espresso powder
• 1 1/2 teaspoons vanilla extract
• 1/4 cup all-purpose flour
• 3/4 teaspoons baking powder
• 3 cups mini-marshmallows