Preheat your oven to 350°F. Grease a 9-inch pie pan or a deep-dish pie plate.
In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.
Add the vanilla extract and eggs to the butter mixture, mixing until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the chocolate chips and M&M's gently with a spatula.
Spread the cookie dough evenly in the prepared pie pan.
Bake for 25-30 minutes, or until the edges are golden brown and the center is set.
Allow the cookie pie to cool in the pan for at least 15 minutes before slicing and serving.