Cream together the butter and sugars in a mixer for 3 minutes until light and fluffy.
Add the eggs and vanilla, making sure to scrape down the sides of the mixing bowl.
Add the flour, salt, baking soda and baking powder and mix on low until everything is incorporated. Fold in 1 ¾ cups of the M&M’s.
Scoop out 2 tablespoons of dough, and transfer to a baking sheet, they can be closely spaced together as this is how they will chill.
Chill the dough for at least 30 minutes if they are scooped into balls. If you’re chilling the dough in the mixing bowl, chill for at least 2 hours.
Preheat your oven to 350 degrees.
Place 12 of the cookie dough balls on a parchment lined baking sheet. Add a few M&M's on top of each cookie, making sure the M&M's stick into the dough.
For cookies that are soft in the middle, bake for 11-13 minutes until just slightly golden around the edges. If you want them crisp, bake for 13-15 minutes. Remove from the oven and let rest for 5 minutes before transferring them off the baking sheet and onto a cooling rack.