Mash three of the bananas in a large mixing bowl until smooth and creamy.

Add the eggs, almond milk, maple syrup, and vanilla extract to the mashed banana and whisk until the mixture becomes smooth and lightly frothy.

Stir in the rolled oats, baking powder, cinnamon, and salt until everything is evenly combined.

Fold in the chopped strawberries so they are distributed throughout the oat mixture.

Pour the batter into the prepared baking dish and spread it evenly with a spatula.

Slice the remaining banana and gently arrange the slices across the top of the oatmeal mixture.

Place the dish in the oven and bake until the center is set and the edges turn lightly golden.

Remove from the oven and allow the baked oats to cool slightly so the texture firms up before slicing.

Cut into squares and serve warm or let cool completely for meal-prep portions.