Heat the oven to 375F
Mash the bananas in a large bowl
Microwave bananas for 2 minutes to intensify their sweet flavor
Add the milk, eggs, and vanilla extract, then whisk to combine
Blend the oats until finely ground
Add blended oats to the bowl along with protein powder, brown sugar, baking soda, and salt
Stir to combine
Fold in most of the chocolate
Spray a 10-inch oven-safe skillet and line with parchment, then spray again
Add the batter and smooth the top
Top with remaining chocolate
Bake until a toothpick comes out clean, 12 to 15 minutes
Sprinkle with flaky salt
Let cool a few minutes, then slice into squares and serve warm
