If you’re looking for an easy dessert that looks super cutee without taking all afternoon, these M&M Oreo Brownies are it. They start with a simple boxed brownie mix (but don’t worry, no one will know!), then get upgraded with crunchy Oreo chunks and bright M&Ms. These are the kind of easy baked goods you can whip up for a last-minute get-together, and they’re one of my favorite easy party desserts when I need something crowd-pleasing that travels well. Plus, since they’re dessert bars that are easy to slice, stack, and serve with no plates or forks required (unless you want them).
Jump to Recipe
Ingredients for M&M Oreo Brownies
Here’s everything you’ll need to make these cute desserts:
- 1 box brownie mix
- Eggs, oil, and water as called for on the box for your brownie mix
- 12-15 Oreos, roughly chopped
- 1 cup M&Ms
How to Make Oreo M&M Brownies
1. Prepare your pan.
Start by preheating your oven to the temperature listed on your brownie mix box. Spray a 9×13-inch pan with cooking spray or line it with parchment paper for easy removal.
2. Mix the brownies.
In a large bowl, prepare your brownie batter according to the instructions on the box. You can use whatever mix you prefer; fudgy or chewy both work great here.
3. Add the mix-ins.
Gently fold in most of the chopped Oreos and M&Ms, but save a decent amount to sprinkle on top later for a fun, festive pop.
4. Spread and bake (partway). Pour the batter into the prepared pan and smooth the top. Pour the batter into the prepared pan and smooth the top. Bake for about 15 minutes, or for about ¾ of the time your box mix tells you to. For me, it said 24 minutes, so that was around 18 minutes.
5. Add toppings. Remove the pan from the oven and sprinkle the reserved Oreos and M&Ms into the top of the brownies. This step keeps the toppings visible and prevents them from sinking.
6. Finish baking. Put your brownies back in the oven until they’re done. You know they’re done when you stick in a toothpick in the middle and it comes out with a couple crumbs (but not dripping in raw batter).
7. Cool and cut.
Let the brownies cool completely in the pan before cutting them into squares. For the cleanest slices, chill the brownies in the fridge for about 30 minutes before cutting.
Pro Tips for M&M Oreo Brownies
- Check your brownie mix box to make sure it specifies that you can bake that mix in a 9×13 pan. Some box mixes only include instructions for 8×8 or 9×9 pans, so they’re not necessarily made to be made in a larger pan. Just to be safe, make sure you see instructions on your box mix for baking in a 9×13 pan.
- Line your pan with parchment paper so you can lift the brownies out easily for slicing; it makes them look cleaner and picture-perfect.
- Don’t overbake. Brownies continue to set as they cool, so it’s better to pull them out when they’re slightly fudgy rather than dry. Now, make sure they’re fully baked too! I found that I actually had to bake mine for about 5 minutes longer than the box mix said I would, but everyone’s oven is different.
- Parbaking before adding toppings keeps your Oreos and M&Ms from sinking into the batter and disappearing. Definitely lean towards parbaking to like three quarters of the way done. I normally try to do about halfway done and then sprinkle on my toppings. However, I found that with these brownies, if I did that the toppings I sprinkled on top had already sunk below the surface by the time the brownies were done.
FAQs
Can I use a homemade brownie recipe instead of a box mix?
Absolutely! I love a boxed mix for convenience, but if you want to go homemade, go for it! This is my favorite homemade brownie recipe, just double it for a 9×13 pan.
Do the M&Ms melt in the oven?
Some will crack a little in the heat, but the ones in the middle of your brownies will be fine. Definitely sprinkles some extra M&Ms on top when your brownies are mostly done so they don’t crack.
Can I make these brownies ahead of time?
Yes! These brownies keep well at room temperature in an airtight container for up to 3 days. You can also freeze them if you wrap tightly in plastic wrap, then in foil, and store for up to 2 months. Thaw at room temperature before serving.
How do I know when the brownies are done baking?
Check with a toothpick inserted in the center. If it comes out with a few moist crumbs (not raw batter), they’re ready. Be wary of the time your box mix says to bake for! At least in my experience, I had to bake these a bit longer than I was expecting, but I’m sure different mixes and different ovens give different results.
Can I make these in a smaller pan?
For sure! Just make sure you adjust your baking time. If you use an 8×8 or 9×9 pan, you’ll have to bake for longer. That also means that you should parbake your brownies for longer before sprinkling extra things on top.
These M&M Oreo Brownies are one of those reliable easy baked goods you’ll keep coming back to. They’re simple, fudgy, and loaded with crunchy Oreos and chocolatey M&Ms in every bite. They’re the perfect dessert bars for potlucks, birthdays, school events, or any time you need easy party desserts that are quick to make and easy to serve. If you’ve got a box mix in the pantry and a sleeve of Oreos, you’re already halfway to a batch, so go ahead and make them the next time you need a fun, shareable treat.
M&M Oreo Brownies
Equipment
- 1 9x13 pan
Ingredients
- 1 box brownie mix Any brand you like. I prefer fudgy brownies that specify on the box that they work for a 9x13 pan
- Eggs, oil, and water as called for on the box for your brownie mix
- 12-15 Oreos roughly chopped
- 1 cup M&Ms plus some extra to sprinkle on top
Instructions
- Start by preheating your oven to the temperature listed on your brownie mix box. Spray a 9x13-inch pan with cooking spray or line it with parchment paper for easy removal.
- In a large bowl, prepare your brownie batter according to the instructions on the box. You can use whatever mix you prefer, but if you're using a 9x13 pan, just make sure the instructions include baking times for a 9x13 pan.
- Gently fold in most of the chopped Oreos and M&Ms, but save a decent amount to sprinkle on top later for a fun, festive pop.
- Pour the batter into the prepared pan and smooth the top. Pour the batter into the prepared pan and smooth the top.
- Bake for about 15 minutes, or for about ¾ of the time your box mix tells you to. For me, it said 24 minutes, so that was around 18 minutes.
- Remove the pan from the oven and sprinkle the reserved Oreos and M&Ms into the top of the brownies.
- Put your brownies back in the oven to finish baking. You know they're done when you stick in a toothpick in the middle and it comes out with a couple crumbs (but not dripping in raw batter).
- Let the brownies cool completely in the pan before cutting them into squares. For the cleanest slices, chill the brownies in the fridge for about 30 minutes before cutting.
