Pumpkin Swirl Brownies - Ultimate Fall Dessert

Ingredients

• 1/2 cup unsalted butter.
• 1 cup granulated sugar.
• 2 large eggs.
• 1 teaspoon vanilla extract.
• 1/3 cup cocoa powder.
• 1/2 cup all-purpose flour.
• 1/4 teaspoon baking powder.
• 1/4 teaspoon salt.
• 1/2 cup canned pumpkin puree.
• 1 large egg yolk.
• 2 tablespoons granulated sugar.
• 1/2 teaspoon ground cinnamon.
• 1/4 teaspoon ground nutmeg.