Enjoy the deliciousness of gluten-free Monster Cookies only in bar form (much easier but just as tasty!).

When I don’t have time to make actual cookies, I love a good cookie bar.

And thankfully, these monster cookie bars are as delicious as their cookie counterpart and much faster and easier than rotating pans of cookies in and out of the oven.

A hand taking a chunk off of an M&M topped oat bar in a small white ramekin.

Believe it or not, transitioning a cookie recipe to a bar cookie recipe isn’t always as easy as piling the entire batch of cookie dough into a 9X13 and calling it good.

After a few little adaptations from my favorite monster cookie recipe, these lovely and delicious monster cookie bars were finally perfected.

A small white ramekin with an M&M topped oat bar inside.

Soft and chewy, they are a perfect sweet treat for any occasion. The colorful M&Ms on top make them all the more special and fun!

The key to these monster cookie bars is to under bake them just slightly. They are incredible warm (serve them with a scoop of ice cream and you’ll be in heaven) and also super tasty cooled and cut into squares.

Cut up M&M topped chocolate oat bars on a white platter.

Monster Cookie Bars

4.48 stars (84 ratings)


  • 2 large eggs
  • cup (141 g) granulated sugar
  • cup (141 g) packed light brown sugar
  • ¼ teaspoon salt
  • 1 teaspoon vanilla extract
  • 1 cup (255 g) creamy peanut butter
  • cup (75 g) salted butter, softened to room temperature
  • 1 ½ cups (255 g) chocolate chips
  • 1 teaspoon baking soda
  • 3 cups (300 g) quick oats
  • 1 cup (198 g) M&M’s


  • Preheat the oven to 350 degrees F. Grease a 9X13-inch baking pan with cooking spray.
  • In a large mixing bowl, combine the eggs and sugars. Mix well. Add the salt, vanilla, peanut butter and butter. Mix until creamy and well combined. Stir in the chocolate chips, baking soda and oatmeal. Mix well.
  • Spread the batter into the prepared pan and press lightly into an even layer. Sprinkle the M&M’s evenly across the top and gently press them into the dough.
  • Bake for 20-25 minutes until the edges are golden and set. Let the bars cool completely in the pan. For a cleaner cut, refrigerate the bars before slicing and serving.


M&M’s: it’s normal for some of the M&M’s to crack while baking. If you want to avoid that, you can add them to the top after you take the bars out of the oven but they won’t sink into the top quite as well.
Serving: 1 Bar, Calories: 254kcal, Carbohydrates: 31g, Protein: 5g, Fat: 13g, Saturated Fat: 6g, Cholesterol: 26mg, Sodium: 158mg, Fiber: 2g, Sugar: 22g

Recipe Source: adapted from this Monster Cookies recipe