cream together butter and the egg yolk

mixed in the white sugar brown sugar and vanilla extract

once mixed add salt and 1 1/2 tablespoons of flour and mix

When cookie batter is mixed add the rest of the flour

after the cookie batter is well mixed add M&Ms to the batter. Mix and flatten dough in a microwave safe coffee cup.

place coffee cup in microwave and cook for 45 to 75 seconds.

The cookie may come out chewy, but that's how I prefer my cookie. you may adjust cook time to your liking.