Cream melted butter and both sugars together until well combined.
Add eggs and vanilla and beat until blended.
In another bowl, combine flour, soda, and salt.
Gradually add flour mixture to butter mixture. Beating well until combined.
Fold in chopped Snickers candy bars and M&Ms by hand.
Refrigerate dough for 1 hour or place in freezer for 25 to 30 minutes.
Preheat oven to 350 degrees F.
Scoop dough into balls with a spring release scoop. I used a 1.5-inch scoop. (Read more about freezing the dough here.)
Place on a ungreased cookie sheet and bake 14 to 15 minutes or until desired degree of doneness is reached. I like soft centers and crisp edges and mine were perfect at 14 minutes.
Remove cookies from the oven and allow cookies to rest undisturbed on cookie sheet for 2 minutes. After 2 minutes move to a wire rack to cool.
Store in an airtight container up to 3 days.