Preheat your oven to 375°F and prepare a muffin tin by greasing it with non-stick spray or lining it with mini liners.
In a bowl, combine the mashed bananas, peanut butter, maple syrup, vanilla extract, almond milk, and egg. Whisk until well combined.
Gently fold in the flour, baking soda, and salt until the batter is smooth.
Spoon the batter into the prepared mini muffin tin, filling each cup about 3/4 full. Add 1/2 teaspoon of jelly on top of each muffin and swirl with a toothpick if desired.
Bake for 12-15 minutes or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the tin for 15-20 minutes before removing and enjoying!