Make sure the oven rack is in the center position and preheat the oven to 350?F.

Sift the flour, baking powder, baking soda, and salt into a medium mixing bowl. Set aside.

Place the butter, granulated sugar, and light brown sugar in the bowl of an electric mixer and cream the ingredients on high speed.

Add the vanilla and egg to the mixer and mix on medium speed.

Stop the mixer and scrape down the sides of the bowl with a rubber spatula. Add the flour mixture and combine on low speed. Itís important to do this on low or youíll get flour all over the kitchen!

Stop the mixer and, using a large spoon or rubber spatula, fold in both kinds of M&Mís.

With a tablespoon, form the dough into balls, using about 2 spoonfuls for each.

Divide the balls of dough among 3 large baking sheets and press to slightly flatten, keeping the cookies about 2 inches apart. You should get 8 cookies on each sheet.

Bake in batches in the oven until golden brown, about 12 to 15 minutes.

Using oven mitts or pot holders, remove the cookies from the oven and transfer them with a plastic turner to wire racks to cool.