Beat butter with sugar in large mixer bowl.
Add in flour, baking soda, cornstarch, and salt and mix.
Next, add in eggs and vanilla.
On low mix in mini chocolate chips.
Drop 2 tablespoons of cookie dough onto parchment lined baking sheets.
Press about 6 mini m&m's into the tops of each cookie.
Bake cookies at 375° for 10 minutes, or until bottoms are golden.
Allow cookies to cool on cookie sheet.