Double Chocolate Banana Muffins - The BakerMama

Ingredients

• 1/2 cup (1 stick) unsalted butter, melted
• 1/2 cup granulated sugar
• 1 large egg
• 1/2 teaspoon vanilla
• 1 cup all-purpose flour
• 2 tablespoons unsweetened cocoa powder
• 1/2 teaspoon baking soda
• 1 cup mashed overripe bananas (about 3 medium bananas)
• 1/2 cup chocolate chips, plus more for garnishing