M&M Oreo Cookie Bars are thick, chewy dessert bars loaded with crushed chocolate sandwich cookie pieces and colorful candy-coated chocolates. They are easier than scooping individual cookies, more playful than a plain blondie, and sturdy enough for lunch boxes, bake sales, birthdays, or a casual movie-night tray.
RECIPE CARD
M&M Oreo Cookie Bars
Ingredients
- 1/2 cup unsalted butter, melted and slightly cooled
- 3/4 cup packed brown sugar
- 1 large egg
- 1 teaspoon vanilla extract
- 1 cup all-purpose flour
- 1/2 teaspoon baking powder
- 1/4 teaspoon salt
- 1 1/2 cups crushed Oreo-style chocolate sandwich cookie pieces
- 3/4 cup M&M-style candy-coated chocolate pieces, plus more for topping
Quick Method
Condensed overview. Use Full Instructions for the complete method, timing and doneness details.
- Mix Dough: Stir melted butter and brown sugar, then mix in egg and vanilla.
- Add Dry Ingredients: Fold in flour, baking powder, and salt until just combined.
- Add Cookies and Candy: Fold in crushed cookies and candy-coated chocolate pieces.
- Bake: Press into a parchment-lined pan and bake until the center is set but still soft.
- Cool and Cut: Cool completely before cutting into squares.
The best cookie bars are soft in the center, lightly golden at the edges, and fully cooled before slicing. This version keeps the method simple while adding the small details that matter: crush the cookies into mixed crumbs and chunks, press the dough evenly, do not overbake, and let the pan cool long enough for clean squares.
Why These Cookie Bars Work
Cookie bars are forgiving because the dough bakes in one pan. You do not need to chill or portion the dough, and the parchment overhang makes it easy to lift the slab out once it cools. Crushed chocolate sandwich cookies add deep cocoa flavor, while the candy pieces bring color and a little crunch.
The texture lands somewhere between a soft cookie and a chewy blondie. Brown sugar helps keep the bars tender, melted butter makes the dough quick to stir together, and a modest amount of baking powder keeps the bars from turning dense.
Ingredients
- 1/2 cup unsalted butter, melted and slightly cooled
- 3/4 cup packed brown sugar
- 1 large egg
- 1 teaspoon vanilla extract
- 1 cup all-purpose flour
- 1/2 teaspoon baking powder
- 1/4 teaspoon salt
- 1 1/2 cups crushed Oreo-style chocolate sandwich cookie pieces
- 3/4 cup M&M-style candy-coated chocolate pieces, plus a few for the top
Cookie and Candy Notes
Use a mix of fine crumbs and small cookie chunks. Fine crumbs flavor the dough, while larger pieces create pockets of chocolate cookie texture. Press a few candy pieces on top before baking so the bars look colorful after they come out of the oven.
If you only have very large cookie pieces, crush them a little more before folding them in. Oversized pieces can make the dough hard to press evenly into the corners of the pan. On the other hand, using only powdery crumbs can make the bars look muddy, so a mixed texture is the sweet spot.
Step 1: Mix the Cookie Bar Dough
Whisk the melted butter and brown sugar until glossy, then mix in the egg and vanilla. Stir in the flour, baking powder, and salt just until no dry streaks remain. The dough should be thick and scoopable, not loose like cake batter.
Fold in the crushed cookie pieces and candy-coated chocolates gently. Overmixing can make the bars tougher and may smear the candy colors into the dough.
Step 2: Press the Dough Into the Pan
Line an 8-inch square baking pan with parchment paper, leaving overhang on two sides. Spread the dough into the pan and press it into an even layer, paying attention to the corners. Add a few extra candy pieces and cookie crumbs on top if you want a more bakery-style finish.
An even layer matters more than a perfectly smooth top. If one side is much thicker, it may stay underbaked while the thinner edge becomes dry.
A 9-inch pan can work, but the bars will be thinner and may bake a few minutes faster. A smaller pan will make thicker bars that need more time. Watch the edges and center rather than relying only on the clock.
Step 3: Bake and Cool
Bake at 350 degrees Fahrenheit until the edges are set and lightly golden, usually 24 to 28 minutes. The center should look set but still soft. A toothpick may come out with a few moist crumbs, which is better than baking until it is completely dry.
Let the pan cool on a wire rack. The bars keep setting as they cool, so slicing too early can make the center collapse or smear.
If the top looks done but the center still jiggles, give the pan a few more minutes and check again. If the edges are browning too quickly, the oven may be running hot. An inexpensive oven thermometer is helpful for dessert bars because a small temperature difference can change the texture.
Step 4: Cut Clean Squares
Once the slab is cool, lift it out using the parchment and place it on a cutting board. Use a sharp knife and wipe the blade between cuts if you want neat edges. For smaller party pieces, cut the slab into 16 squares. For larger bakery-style bars, cut 9 squares.
If the bars are very soft, chill them for 15 to 20 minutes before slicing. A short chill firms the chocolate and makes the cuts cleaner without drying the bars out.
Serving and Party Ideas
These bars are easy to serve because they do not need frosting, forks, or plates. Add them to a dessert board, pack them in treat bags, or stack them on a platter with parchment between layers. They pair well with milk, coffee, or a scoop of vanilla ice cream.
For birthdays or school treats, cut smaller squares so they are easier to handle. For a bake sale, wrap each square tightly once fully cooled and add a small label outside the wrapper if needed.
A little extra color on top makes the bars easier to spot on a crowded dessert table.
Storage Tips
Store M&M Oreo Cookie Bars in an airtight container at room temperature for 3 to 4 days. Place parchment between layers so the tops stay neat. If your kitchen is warm, refrigerate them, then let them sit at room temperature for a few minutes before serving.
They also freeze well. Wrap individual squares, place them in a freezer-safe container, and thaw at room temperature when you want a quick sweet treat.
For parties, bake the bars the day before and cut them once fully cool. The texture is often even better after the crumb has settled overnight, and you avoid rushing the slicing step right before serving.
Tips for Perfect Cookie Bars
- Do not crush all the cookies into powder. A mix of crumbs and chunks gives the best texture.
- Let melted butter cool slightly so it does not scramble the egg.
- Line the pan with parchment for easy lifting and cleaner slicing.
- Pull the bars when the center is set but still soft, since they firm up as they cool.
- Cool fully before cutting if you want tidy squares.
More Dessert Ideas
For more sweet recipes, try Homemade Chocolate Caramel and Pecan Turtle Clusters, Empty Tomb Rolls, Frozen Greek Yogurt-Covered Blueberries, or browse more Food & Drink ideas.
M&M Oreo Cookie Bars are at their best when they look a little playful but still slice cleanly. Keep the dough thick, bake gently, cool patiently, and the bars will be chewy, colorful, and easy to share.