Ingredients
Scale
- 1 cup (226g) unsalted butter, softened
- 1/2 cup (100g) granulated sugar
- 1 cup (200g) packed light brown sugar
- 2 large eggs
- 2 teaspoons pure vanilla extract
- 2 1/4 cups (270g) all-purpose flour
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 1 1/2 cups (250g) M&M’s Candies (divided)
- For the Whipped Vanilla Buttercream:
- 1/2 cup (113g) unsalted butter, softened
- 3-4 cups (360-480g) powdered sugar
- 2-4 tablespoons heavy cream
- 1 teaspoon pure vanilla extract
- Pinch salt
- 1/2 cup (80g) extra M&M’s (for topping)
Instructions
- Start by preheating your oven to a delightful 350°F (175°C) and lightly grease a 9×13 inch baking pan, lining it with parchment paper so that the paper overhangs slightly on the sides. This creates convenient “handles” for easy removal later.
- In a large mixing bowl, either with a stand mixer fitted with the paddle attachment or with a hand mixer, cream together the softened unsalted butter, granulated sugar, and packed light brown sugar until the mixture is light, fluffy, and impeccably smooth, which typically takes about 2-3 minutes. This aeration process is key to a tender, chewy bar. Next, crack in the two large eggs, one at a time, beating well after each addition to fully incorporate them into the sugary butter. Then, stir in the pure vanilla extract, ensuring it’s evenly distributed throughout the wet ingredients.
- In a separate medium bowl, whisk together your all-purpose flour, baking soda, and a pinch of salt until thoroughly combined; this ensures leavening agents and salt are evenly distributed.
- Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix, as this can lead to tough bars! Overmixing develops the gluten too much, robbing your bars of that perfect chew. Once the dough comes together, gently fold in about two-thirds of your M&M’s candies. The dough should be thick and slightly sticky, not runny or crumbly.
- Press the dough evenly into your prepared 9×13 inch baking pan, ensuring it fills the corners and has a relatively flat surface. Sprinkle the remaining M&M’s over the top of the pressed dough, lightly pressing them in to adhere. Bake for 25-30 minutes, or until the edges are golden brown and the center is set but still looks slightly soft. A toothpick inserted into the center should come out with moist crumbs, not wet batter. Avoid overbaking if you want those supremely chewy centers! Once baked, let the bars cool completely in the pan on a wire rack before frosting and slicing. Cooling is crucial for the bars to set and for easier handling.
- To create silky smooth and fluffy whipped vanilla buttercream, combine the softened unsalted butter in a large mixing bowl. Using an electric mixer on medium-high speed, beat the butter for 2-3 minutes until it becomes light, pale, and incredibly fluffy. This step is essential for incorporating air and achieving a delicate texture. Gradually add the powdered sugar, one cup at a time, beating well after each addition until fully incorporated and smooth. The mixture will be quite thick at this stage. Next, slowly pour in the heavy cream and a generous splash of pure vanilla extract, then add a tiny pinch of salt to balance the sweetness. Continue beating on medium-high speed for another 3-5 minutes until the buttercream is light, fluffy, and has a wonderfully velvety consistency. If it’s too thick, add a tiny bit more cream; if it’s too thin, add a little more powdered sugar until it reaches that perfect spreadable yet pipeable texture.
- Once your M&M Cookie Bars are completely cooled – and this is a crucial step for perfect frosting – gently spread the luscious whipped vanilla buttercream evenly over the top surface. You can use an offset spatula or the back of a spoon to create lovely swirls and peaks, giving it an artisanal touch. Ensure the frosting reaches all the edges, creating a complete blanket of creamy deliciousness. For that extra festive spark and visual appeal, generously sprinkle the extra M&M’s candies over the frosted bars. You can even gently press some into the frosting for better adherence. Now, with a sharp knife, carefully cut the large slab into individual bars. Smaller, bite-sized squares are often perfect, or you can cut larger rectangles for a heartier treat. Each bar should showcase a beautiful layer of cookie, frosting, and colorful M&M’s, ready to be devoured.
Notes
These M&M Cookie Bars are thick, chewy, golden brown, and absolutely loaded with vibrant, candy-coated M&M’s. They’re soft, buttery, and utterly irresistible—the ultimate crowd-pleaser for any occasion, promising a nostalgic indulgence.
- Prep Time: 20 minutes
- Cook Time: 30 minutes
- Category: Dessert
- Cuisine: American