Preheat the oven to 350F and grease an 8x8 baking dish with olive oil or unsalted butter.
Place 1 cup of the rolled oats and 1 cup of milk into a blender and pulse until oats are finely chopped.
Mix Greek yogurt, mashed banana, vanilla extract, and egg in a bowl until just combined.
Then add the second cup of oats, salt, and cinnamon into the bowl. Stir to combine.
Pour the blended oat & milk mixture into the bowl and ensure that everything is mixed well.
Gently fold the frozen blueberries into the oat batter.
Pour batter into the prepared baking dish, top with more frozen blueberries if desired, and bake at 350F for 35-40 minutes or until edges are golden and the top is set.
Allow to cool and set for 10 minutes, cut into squares, top however you’d like, and enjoy!