- Preheat oven to 350 degrees. Prepare a 9x13-inch baking dish by spraying well with nonstick cooking spray.
- Mix the wet ingredients (milk through flaxseed) together in a large bowl. Stir in the dry ingredients (oats, protein powder, powdered peanut butter, and spices) and mix until combined.
- Spoon the oat batter into the prepared baking dish. Bake for 25-28 minutes or until the center is just set and the edges are a light golden brown.
- Cool the baking dish on a cooling rack until room temperature. Drizzle with peanut butter (if your peanut butter is very thick, warm in the microwave for 30 seconds before drizzling.) Slice into 12 squares.
- Serve warm, topped with banana slices or chopped nuts if desired (macros for additional toppings not included.)
This recipe is freezer friendly - freeze the squares in a freezer safe zip-top bag for up to 3 months. Defrost individual squares in the microwave for 30-60 seconds on medium power.
You could also try other flavors of Optimum Nutrition Gold Standard 100% Whey protein powder in this recipe. Chocolate, mocha cappuccino, chocolate peanut butter, or salted caramel would be particularly delicious!