Two oatmeal brownie squares stacked on a white plate

Oatmeal Brownie Recipe – Easy Fudgy Chocolate Dessert

Oatmeal Brownie is a simple one-bowl treat made by whisking peanut butter, maple syrup, and milk, then stirring in oats and cocoa before baking into thick, fudgy squares. The oats give it a hearty bite while the cocoa keeps it rich and brownie-like.

These brownies are for the days you want something chocolatey and satisfying without pulling out a stand mixer or dealing with a long ingredient list.

They bake up thick, soft in the middle, and sturdy enough to slice into clean squares once they cool.

Why You’ll Love This Recipe

  • One bowl, no complicated steps
  • Fudgy, chocolate-forward texture with a hearty oat bite
  • Sweetened with maple syrup
  • Easy to slice for snacks, lunchboxes, or dessert
  • Customizable with chocolate chips, nuts, or a pinch of espresso powder
Plated oatmeal brownie squares showing the thick edges
Slice and serve

Ingredients

Candy base

Wet ingredients

  • 1/3 cup (80 g) peanut butter (homemade or store-bought)
  • 1/2 cup (120 g) maple syrup
  • 2 cups (480 ml) milk of your choice
  • 1 tsp vanilla extract

Dry ingredients

  • 2 cups (180 g) rolled oats
  • 1/4 cup (30 g) cocoa powder
  • 1 tsp baking powder
  • 1/4 tsp salt
  • 1 tbsp ground flaxseed (optional)

Finish

Optional topping

  • 1/3 cup (60 g) chocolate chips
Overhead view of oats, milk, cocoa powder, peanut butter, maple syrup, and other ingredients
Everything you need

Ingredient Notes & Substitutions

  • Peanut butter: Any creamy nut/seed butter works (almond butter, cashew butter, sunflower seed butter). If yours is unsalted, keep the salt in.
  • Maple syrup: Honey works too (same amount), but maple gives the cleanest flavor with cocoa.
  • Milk: Dairy or non-dairy both work. Use unsweetened almond/oat milk if you want the chocolate to stand out more.
  • Cocoa powder: Natural or Dutch-process both work. If your cocoa is very dark, you may want the optional chocolate chips for extra sweetness.
  • Ground flaxseed: Helps tighten the texture slightly, but you can skip it with no problem.
  • Chocolate chips: Sprinkle on top or fold in. Mini chips spread more evenly.
Hand holding a fudgy oatmeal brownie square with oats and chocolatey crumb
Fudgy bite

How to Make Oatmeal Brownie

  • Prep the pan and oven. Preheat the oven to 350°F (175°C). Line an 8-inch square pan with parchment paper.
  • Mix the wet ingredients. In a large bowl, whisk the peanut butter and maple syrup until smooth. Pour in the milk and vanilla, then whisk again until fully combined.
  • Add the dry ingredients. Stir in the rolled oats, cocoa powder, baking powder, salt, and ground flaxseed (if using). Mix until you have a thick, chocolatey batter.
Peanut butter and maple syrup whisked together in a glass bowl
Start the batter
  • Pour the batter into the prepared pan and spread it evenly. Sprinkle chocolate chips on top if using.
Oats and cocoa added to wet ingredients in a mixing bowl
Add the dry ingredients
  • Bake until set and no longer wet in the center (about 25–30 minutes).
Oatmeal brownie batter baking in a parchment-lined pan
Bake until set
  • Cool and slice. Let the pan cool completely so the brownies firm up, then lift out using the parchment and cut into squares.
Cutting baked oatmeal brownie into squares and holding one piece
Cool, then slice

Expert Tips

  • Let it cool all the way before slicing for the cleanest squares. Warm brownies will be soft and may crumble.
  • Press the batter flat in the pan so the brownies bake evenly edge-to-center.
  • For a deeper chocolate flavor, add 1–2 tsp instant espresso powder with the cocoa.
  • Want it sweeter? Use chocolate chips on top and choose sweetened milk (or add 1–2 tbsp extra maple syrup).
  • If your batter looks thinner than expected, let it sit 3–5 minutes so the oats absorb liquid before baking.
  • For thicker brownies, use an 8-inch pan; for thinner squares, use a 9-inch pan and reduce bake time slightly.
  • Use quick oats only if that’s what you have—texture will be softer and more cake-like.

Storage & Freezing

  • Fridge: Store in an airtight container for up to 5 days.
  • Freezer: Wrap individual squares and freeze in a freezer-safe bag for up to 2 months.
  • Thawing: Thaw overnight in the fridge or at room temperature for 30–60 minutes. Warm briefly (10–15 seconds) if you like them softer.
Fudgy oatmeal brownie cut into squares in a lined pan
Fudgy oatmeal brownie squares

Variations

  • Peanut Butter Chocolate Swirl: Dollop extra peanut butter on top and swirl before baking.
  • Double Chocolate: Fold chocolate chips into the batter and sprinkle more on top.
  • Orange-Chocolate: Add 1 tsp orange zest to the batter.
  • Nutty Crunch: Add 1/3 cup chopped walnuts or pecans.
  • Mocha: Add espresso powder and a pinch of cinnamon for a café-style flavor.
Hand holding a fudgy oatmeal brownie square with oats and chocolatey crumb

Oatmeal Brownie

Fudgy baked oatmeal brownie squares made with peanut butter, maple syrup, cocoa, and rolled oats. Easy, one-bowl, and perfect for slicing.
Prep Time 10 minutes
Cook Time 30 minutes
chill time 30 minutes
Total Time 1 hour 10 minutes
Servings: 9 squares
Course: Dessert
Cuisine: American
Calories: 240

Ingredients
  

  • 1/3 cup 80 g Homemade Peanut butter or store-bought
  • 1/2 cup 120 g Maple syrup
  • 1/4 teaspoon Salt
  • 2 cups 480 ml Milk of your choice
  • 1 teaspoon Vanilla extract
  • 2 cups 180 g Rolled oats
  • 1/4 cup 30 g Cocoa powder
  • 1 tablespoon Ground flaxseed optional
  • 1 teaspoon Baking powder
  • 1/3 cup 60 g Chocolate chips (optional)

Equipment

  • 8-inch square baking pan
  • Parchment paper
  • Large mixing bowl
  • Whisk
  • Spatula
  • Measuring cups and spoons

Method
 

  1. Preheat oven to 350°F (175°C). Line an 8-inch square pan with parchment paper.
  2. In a large bowl, whisk peanut butter and maple syrup until smooth.
  3. Add milk and vanilla extract; whisk until combined.
  4. Stir in rolled oats, cocoa powder, ground flaxseed (if using), baking powder, and salt until thick and evenly mixed.
  5. Pour batter into the prepared pan and spread evenly. Sprinkle chocolate chips on top if using.
  6. Bake 25–30 minutes, until set in the center.
  7. Cool completely, then lift out and slice into squares.

Nutrition

Calories: 240kcalCarbohydrates: 33gProtein: 8gFat: 10gSaturated Fat: 3gPolyunsaturated Fat: 3gMonounsaturated Fat: 4gCholesterol: 8mgSodium: 135mgPotassium: 170mgFiber: 5gSugar: 18gVitamin A: 120IUCalcium: 90mgIron: 2mg

Video

Notes

  • Preheat oven to 350°F (175°C). Line an 8-inch square pan with parchment paper.
  • In a large bowl, whisk peanut butter and maple syrup until smooth.
  • Add milk and vanilla extract; whisk until combined.
  • Stir in rolled oats, cocoa powder, ground flaxseed (if using), baking powder, and salt until thick and evenly mixed.
  • Pour batter into the prepared pan and spread evenly. Sprinkle chocolate chips on top if using.
  • Bake 25–30 minutes, until set in the center.
  • Cool completely, then lift out and slice into squares.

Tried this recipe?

Let us know how it was!

FAQs

Can I use quick oats instead of rolled oats?

Yes. The brownies will be softer and less chewy, but they still bake up well.

Do these brownies taste like peanut butter?

A little. The cocoa leads, and the peanut butter gives richness in the background.

How do I know when they’re done?

The center should look set (not wet) and the edges should feel firm. They’ll continue to firm as they cool.

Can I make this dairy-free?

Yes—use any non-dairy milk you like.

Why do I need to cool before slicing?

Cooling helps the oats and cocoa set, giving you clean squares instead of crumbly pieces.

Can I reduce the maple syrup?

You can slightly (by 1–2 tbsp), but reducing too much can make them drier and less brownie-like.

Key Takeaways

  • Oatmeal Brownie is an easy one-bowl recipe using peanut butter, maple syrup, and cocoa for a fudgy texture.
  • This recipe is customizable with options like chocolate chips, nuts, or espresso powder.
  • Bake for 25-30 minutes for thick, chocolatey brownies that are easy to slice once cooled.
  • Storage tips include keeping them in the fridge for up to 5 days or freezing for 2 months.
  • Variations like Peanut Butter Chocolate Swirl or Mocha add unique flavors to the Oatmeal Brownie.

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Estimated reading time: 6 minutes

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