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PB Banana Protein Oatmeal Squares

It’s meal prep time! These Peanut Butter Banana Protein Oatmeal Squares take plain oatmeal to the next level with banana, peanut butter, cinnamon, and an extra boost of protein. Bake a batch in under 40 minutes, slice, freeze, and you’re set for breakfast or snacks for weeks! 

Makes: 12 squares

Serving Size: 1 square

Prep Time: 10 minutes

Total Time: 35 minutes

Nutrition Facts: 248 calories / 34.5g carbs / 15g protein / 6.5g fat 

PB Banana Protein Oatmeal Squares


  • 3 cups (735g) nonfat milk

  • 2 medium (236g) bananas (mashed)

  • 3 tablespoons (20g) ground flaxseed

  • 5 cups (400g) old fashioned oats

  • 3 scoops (96g) Optimum Nutrition Gold Standard vanilla whey protein powder

  • ¼ cup (22g) powdered peanut butter

  • 2 teaspoons cinnamon

  • 1 ½ teaspoons baking powder

  • ½ teaspoon salt

  • ¼ cup (69g) natural smooth peanut butter


  1. Preheat oven to 350 degrees. Prepare a 9x13-inch baking dish by spraying well with nonstick cooking spray.

  2. 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.

  3. 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.

  4. 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.

  5. Serve warm, topped with banana slices or chopped nuts if desired (macros for additional toppings not included.)


  1. 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.

  2. You could also try other flavors of Optimum Nutrition Gold Standard whey protein in this recipe. Chocolate, mocha cappuccino, chocolate peanut butter, or salted caramel would be particularly delicious!

  3. If you decide to use our favorite Optimum Nutrition protein powder you can use code "MACROSTAX" for 20% off your purchase!

Some of the links above are affiliate links, which may earn Macrostax a commission at no extra cost to you.

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