Preheat your oven to 180C/350F. Line an 8 x 8-inch pan with parchment paper.
In a large mixing bowl, combine the rolled oats, mashed bananas, peanut butter, and vanilla extract. Stir until fully incorporated.
Gently fold in the chopped strawberries.
Transfer the batter into the lined pan and spread it out evenly. Top with any extra strawberries if desired.
Bake in the oven for 20 to 25 minutes, until golden brown and a skewer comes out clean.
Let the bars cool in the pan for at least 10 minutes before transferring to a wire rack to cool completely.