Marshmallows are baked into an M&M cookie base, making the perfectly toasted marshmallow gooey cookie bars.
1cup(2 sticks) unsalted butter, softened
1cupdark brown sugar
2teaspoonspure vanilla extract
2 1/2cupsall-purpose flour
24jumbo(regular size) marshmallows
Preheat oven to 375 degrees F. Lightly grease a 9x13-inch baking pan with nonstick spray (I recommend Baker's Joy).
In a large mixing bowl, beat together the butter and sugars until creamy, about 2 minutes. Add the eggs, one at a time, beating after each addition. Mix in the vanilla.
In a separate medium bowl, whisk together the flour, baking soda and salt. Gradually add to the wet ingredients and beat until just combined. Gently mix in the M&M's until evenly distributed.
Press just less than 3/4 of the cookie dough evenly into the bottom of the prepared baking pan. Layer the 24 marshmallows into the pan, spacing evenly into a 4x6 grid. Use a medium cookie scoop or ice cream scoop to spoon dough balls in between each marshmallow in the 6-count rows, creating 20 dough balls (5 in each row).
Bake for 25 minutes, or until the marshmallows and cookie dough are dark golden brown. Let cool before slicing into 24 squares.