Preheat the oven to 350 degrees.
Microwave the butter for about 40 seconds to just barely melt it. If there is still a piece of butter that isn't melted then swirl it until it melts {you don't want the butter to be hot or the eggs will curdle}.
Add both sugars and mix until creamy {by hand works great}. Add the vanilla and the egg, mix until incorporated but do not over mix or the dough will be stiff.
Add the flour, baking soda, and salt. Mix until everything is incorporated. Add the chocolate chips and stir until they are evenly distributed.
Scoop the dough with a medium cookie scoop {or about 2 tablespoons} into your hand and roll until smooth. Place on a silicone {or parchment} lined baking sheet.
Bake for 9-11 minutes. You want to remove them from the oven when they are puffy and just starting to turn golden. The key to getting the super soft cookie is to not over bake them. While the cookies are baking, cut half of your M&M's in half.
Once you remove them from the oven immediately add the bunny face {a whole M&M} and the bunny ears {M&M cut in half}, being sure to press the candy into the cookie. Allow the cookies to cool completely on the baking sheet.
Store in an airtight container at room temperature {or in the refrigerator} for up to 4 days or freeze for up to 3 months.