Preheat your oven to 350°F (175°C) and grease an 8x8-inch baking pan or line it with parchment paper.
In a large mixing bowl, combine the mashed bananas and peanut butter until smooth.
Stir in the cocoa powder, salt, and vanilla extract until fully incorporated.
If using, fold in the chocolate chips.
Pour the batter into the prepared baking pan and spread it evenly.
Bake for 20-25 minutes, or until a toothpick inserted into the center comes out mostly clean.
Allow the brownies to cool in the pan for about 10 minutes before slicing into squares.