Preheat the oven to 350°F (175°C). Grease and flour a loaf pan or line it with parchment paper for easy removal after baking.

Mash the bananas. In a large bowl, peel the ripe bananas and mash them with a fork until smooth, leaving a few small chunks for texture.

Mix the wet ingredients. In a separate bowl, beat together the softened butter, peanut butter, and sugar until light and fluffy. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract and the mashed bananas.

Combine the dry ingredients. In another bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Avoid overmixing to keep the bread tender.

Add the milk. Pour in the milk and stir until everything is well incorporated. The batter should be smooth and thick, with a slight pourability.

Bake. Pour the batter into your prepared loaf pan and spread it evenly. Bake for 60–65 minutes or until a toothpick inserted into the center comes out clean.

Cool and enjoy. Let the bread cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely. Slice and enjoy your delicious peanut butter banana bread!