Combine flour, baking powder and baking soda in a bowl
In a different bowl, beat the egg, brown sugar and white sugar in a bowl until light and fluffy. Mix in egg and vanilla on until combined. Stir in flour mixture.
Mix in the M&M's, setting some aside to be used later.
Scoop small balls of dough out of the mixture, about 2 tablespoons each. Place balls on baking tray. Press the remaining m&m's into the cookies. Be careful no to flatten the dough as it will spread.
Bake for 10-12 minutes, until the edge of the cookie is just starting to crisp. For those who prefer a crisper cookie, bake for another 2-4 minutes.
Place the baking sheets on a wire rack until completly cool. Do not try and move the cookies while they are still hot as they will break. The cookies will firm up as they cool.