M&M Oat Chocolate Chip Cookie Bars

by Jess Italiano on Feb 8, 2024 (updated Oct 11, 2024)

These M&M oat chocolate chip cookie bars are soft and gooey, full of melty chocolate and M&Ms, and are so easy to make! With no mixer required and common pantry ingredients, these bars come together quickly for the perfect pick-me-up treat!

These M&M oat chocolate chip cookie bars are such a fun & easy treat to make. All you need is a bowl, whisk, rubber spatula, and you’re good to go! These bars are thick, chewy, nutty from the rolled oats, and super chocolatey from chocolate chips and M&Ms.

Why you’ll love these M&M oat chocolate chip cookie bars

No mixer required. These bars come together super quickly. No mixer is required – all you need is a bowl & a whisk!
Nutty & chocolatey flavor. The nuttiness from the rolled oats, paired with the melty chocolate chips and M&Ms, make these bars incredibly tasty.
Versatile recipe. These bars can be customized with different mix-ins and spices! Replace the cinnamon with a little nutmeg, add a different candy, etc. The options are endless!

Ingredient notes

Oats: old fashioned rolled oats work best in this recipe – they add the best nutty flavor and chewy texture.
All purpose flour: all purpose flour provides the best texture for these bars.
Leavening agents: both baking powder & baking soda are used to help these bars rise tall in the pan.
Fine sea salt: salt is just as important in baking as it is in cooking! Salt enhances flavor, so omitting it would definitely make a difference in the final result.
Ground cinnamon: cinnamon adds warmth to the bars and enhances the depth of flavor.
Butter: unsalted butter is preferred to avoid adding too much salt to the recipe.
Sugar: light brown sugar and granulated sugar are used for sweetness and moisture.
Eggs: the eggs act as a binding agent for the ingredients.
Vanilla: good quality vanilla extract is key for the best flavor.
Mix-ins: mini chocolate chips and M&Ms are added for pockets of melty chocolate all throughout! Feel free to add or change up the mix-ins to your liking.

See the recipe card at the end of this post for the full list of ingredients & their quantities.

Recipe summary

Below is a condensed version of the recipe steps. See the recipe card at the end of this post for the full recipe instructions.

Whisk dry ingredients. Whisk together the oats, flour, baking powder, baking soda, salt, and cinnamon. Set aside.
Whisk wet ingredients. Separately, whisk together the melted butter, brown sugar, and granulated sugar until combined. Add the eggs and vanilla extract and mix.
Combine. Add the dry ingredients to the wet ingredients and fold until about half way incorporated. Add the chocolate chips and M&Ms and fold until evenly incorporated and the flour is fully mixed in.
Bake. Press the mixture into an 8×8 inch pan lined with parchment paper. Bake at 350F for 25-30 minutes until set and the tops are golden brown.

FAQ

How should these bars be stored?

Store in an airtight container at room temperature. The bars will stay fresh for 4-5 days if stored properly. Put in the fridge/freezer for longer storage.

Can I use a different sized pan?

Yes! A 9×9 inch pan will also work well, but the bake time may be slightly less. Keep the bake time in mind if you are using a different type of pan.

Can I use other types of oats?

Quick cooking oats will also work here! Definitely do not use steel cut.

How do I freeze these bars?

Once completely cool, slice the bars into squares and place on a baking sheet in the freezer until firm. Once firm, transfer to a Ziplock bag or storage container and freeze for 2-3 months.

Baking tips

Use a kitchen scale. I cannot stress this enough – a kitchen scale is the only way to ensure accurate results. They are cheap and will make cleaning up SO much easier.
Accurately measure the flour. One of the most common mistakes in baking is over-measuring flour. If you don’t have a kitchen scale, spoon the flour into a measuring cup and level it off with a knife. This will prevent the flour from being over-packed.
Don’t over-mix. Over-mixing can make these bars dense and tough. The purpose of mixing through the chocolate chips and M&Ms before the flour is fully incorporated is to avoid over-mixing. Make sure to stop folding once the dough has just come together.

Baking in grams

I rely on gram measurements when testing recipes because they offer the highest level of accuracy (and less cleanup!). Unlike volume measurements, which can vary, grams provide a reliable and consistent standard. I carefully test all of my recipes using this kitchen scale, therefore I cannot guarantee the outcome when using volume measurements. However, volume measurements are available in the recipe card.

Other bar and brownie recipes to try

Have you tried this recipe? I would love to know how it turned out! Leave a star rating & review below and tag @sturbridgebakery on Instagram so I can see photos & videos of your yummy bakes! Want to save this recipe for later? Tap the heart button on the right side of your screen!