Preheat your oven to 350 degrees
Grease a 9 inch square or 10 inch square
In a large bowl, Mix all of the dry stuff - flour, sugar, and baking powder
In a small bowl, mix the wet ingredients - melted butter, eggs, vanilla
Add the wet ingredients to the dry
Mix well
Fold in the M&Ms and chocolate chips
The dough will be thick, kind of like play dough, so it really won't pour out into your pan. It will do more of a plop into your pan. Push the dough out to the edges making sure the depth looks pretty even.
Bake for about 25-30 minutes, or until the top starts turning a little crusty and golden, and a toothpick inserted into the middle comes out clean
Enjoy with a tall glass of milk or ice cream!