Decadent Marshmallow Chocolate Bars

Ingredients

• 3/4 cup butter, softened
• 1-1/2 cups sugar
• 3 large eggs, room temperature
• 1 teaspoon vanilla extract
• 1-1/3 cups all-purpose flour
• 3 tablespoons baking cocoa
• 1/2 teaspoon baking powder
• 1/2 teaspoon salt
• 1/2 cup chopped nuts, optional
• 4 cups miniature marshmallows
• TOPPING:
• 1-1/3 cups semisweet chocolate chips
• 1 cup peanut butter
• 3 tablespoons butter
• 2 cups Rice Krispies