Preheat oven to 375 degrees and line two baking sheets with parchment paper.
Whisk together the flour, baking soda and salt in a medium bowl and set aside.
In a large bowl, beat the butter, both sugars and vanilla for 3-4 minutes, until creamy. Add in eggs one by one, beating after each addition.
Add flour mixture all at once and stir in until just blended (don't overmix!). Add in the M&M's and stir until combined.
Drop by tablespoons, or using a mini cookie scoop, on baking sheet. Bake for 10-12 minutes or until golden brown.
Enjoy, or top with more M&M's while still warm, and then enjoy! ;)