Preheat your oven to 350°F (175°C) and prepare your loaf pan by greasing it or lining it with parchment paper.

In a large mixing bowl, whisk together the mashed bananas, melted vegan butter, maple syrup, almond or oat milk, and vanilla extract until smooth.

In a separate bowl, combine baking powder, baking soda, cinnamon, salt, all-purpose flour, and rolled oats, mixing them thoroughly.

Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.

In a small bowl, combine melted vegan butter, light brown sugar, and cinnamon to create the cinnamon swirl.

Pour half of the batter into the loaf pan, drizzle half of the cinnamon mixture on top, layer the remaining batter, then top with the rest of the cinnamon mixture. Swirl with a knife.

Bake for approximately 45 minutes, or until a toothpick in the center comes out clean.

Let the bread cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.