These M&M cookie bars are perfect for celebrating a birthday and St. Patty's Day. They're colorful, fun, and deliciously chewy, and you can customize the M&M colors to match your theme!
1: Cream butter and sugars until combined.
2: Add vanilla and eggs until combined.
3: Stir flour, salt, and baking soda together, then add into the mixture one cup at a time until combined and smooth.
4: Add in 3/3 of the bag of m&ms.
5: Spread the mixture into a buttered 9x13 baking dish, pressing lightly to spread evenly.
6: Bake at 350°F for exactly 20 minutes.
7: Let it sit at room temperature for 1 hour after baking before serving.
