Adapted from Cook's Illustrated's Perfect Chocolate Chip Cookies
14 tablespoons butter
1/2 cup sugar
3/4 cup dark brown sugar
2 teaspoons vanilla
1 egg yolk
1/2 teaspoon salt
1/2 teaspoon baking soda
1 3/4 cup flour
3/4 cup white chocolate M and M's (or favorite flavor), plus more to garnish
4 ounces semi-sweet chocolate, chopped into small chunks
Preheat oven to 375º.
Melt 10 tablespoons of the butter in a saucepan over medium high heat till melted. Continue cooking a couple more minutes till butter is golden brown with a nutty fragrance. Pour into heatproof bowl, and add the remaining 4 tablespoons of butter. Stir till melted.
Add sugars, then vanilla. Mix in egg and egg yolk. Add baking soda, then flour and mix till just combined. Add M and M's and chocolate chunks.
Use 4 tablespoon (1/4 cup) scoop to make dough balls. Place about 2 inches apart on parchment lined cookie sheets. Bake 10-14 minutes or till cookies are golden. Press a few extra M and M's into warm cookies to garnish. Cool on rack.
Makes about 12 large cookies.