Fluffernutter Bars with Gooey Marshmallow Swirls - My Home Made Recipe

Ingredients

• 1/2 cup (113 g) unsalted butter, softened
• 1/2 cup (130 g) creamy no-stir peanut butter
• 1 cup (200 g) packed light brown sugar
• 1 large egg, room temperature
• 2 teaspoons vanilla extract
• 1 1/2 cups (190 g) all-purpose flour
• 1/2 teaspoon baking powder
• 1/2 teaspoon fine salt
• 1 jar (7 oz or 198 g) marshmallow creme
• 1/4 cup (65 g) creamy peanut butter, warmed until pourable
• Nonstick spray, for the spatula and knife