Preheat oven to 350 F.
In a stand mixer, cream the butter and sugar. Mix in the vanilla and eggs. Add the flour, baking soda and salt and mix until dough forms. (Ideally, you'll refrigerate the dough for at least 2 hours!)
Mix in the mini chocolate chips and regular M&Ms. Drop by Tbsp onto baking sheets.
Bake for 10-11 minutes, or until golden around the edge and soft in the middle. Remove from oven and nestle 1 or 2mega M&Ms into each cookie, before they cool down.
Let cook for 5-10 minutes before serving.
Serve Mega M&M Valentine's Cookies.