3/4 cup unsalted butter, melted1 cup packed brown sugar 1/2 cup white sugar1 whole egg 1 egg yolk1 tbsp. vanilla extract2 1/4 cups all purpose flour1/2 tsp. salt1/2 tsp. baking soda2 cups milk chocolate chips (or 1 cup milk chocolate chips, 1 cup m&m's)Preheat oven to 325 degrees. Line cookie sheets with parchment paper. In a large bowl, whisk together butter and sugars until combined (about 2 minute). Add in vanilla and egg + yolk. Whisk until smooth (about 30 seconds).Add flour, salt, and baking soda to the bowl- stir together with a spatula or wooden spoon until there are no streaks of flour. Fold in the chocolate until evenly distributed.Using a 1 1/2 T cookie scoop (or two spoons), drop dough 2 inches apart onto prepared cookie sheets. Bake for 11-13 minutes (cookies will look underdone, and bottoms will be barely golden). Cool on cookie sheet for 5 minutes. Makes 3 dozen cookies.