01 -
Preheat oven to 350°F. Line an 8x8-inch baking pan with aluminum foil and spray with cooking spray
02 -
In a large microwave-safe bowl, melt the butter. Let it cool slightly before continuing
03 -
Add peanut butter, egg, brown sugar, and vanilla to the melted butter. Whisk until the mixture is smooth
04 -
Stir in the flour just until combined, being careful not to overmix
05 -
Gently fold in ½ cup of M&M's into the batter
06 -
Pour batter into prepared pan and smooth the top. Sprinkle remaining ¼ cup M&M's on top and press lightly
07 -
Bake for 22-26 minutes until a toothpick comes out clean or with just a few moist crumbs
08 -
Let blondies cool in the pan for at least 1 hour before cutting