Preheat oven to 375 degrees. In a large mixing bowl, combine 2 cups oatmeal and 1 cup brown sugar.
Add 1 1/2 cup flour.
Add 1 teaspoon baking soda and 1/2 teaspoon salt.
Mix thoroughly.
Add 1 cup melted butter. Mix again.
Set aside 1 1/2 cup mixture for later.
Pour remaining mixture into 9″ x 13″ greased pan.
Spread evenly across pan. Bake in oven for 12 minutes.
In a small mixing bowl, add 1/3 cup peanut butter.
Add 1 can sweetened condensed milk.
Stir.
When 12 minutes are finished, remove pan from oven.
Coat with peanut butter and condensed milk mixture.
In separate bowl, combine reserved oatmeal mixture and 1 cup M&M’s.
Add that mixture to the top of the peanut butter layer.
Spread evenly. Place back in oven for 20 to 22 minutes or until golden brown. Serve and enjoy!