Beat until fluffy:

3/4 c. butter
1/2 c. sugar
1/4 tsp. salt

Add and beat well:

1 egg
1/2 tsp. vanilla

Add:

1 3/4 c. flour

Shape into balls and add M & M's or mini chocolate chips to center of balls. Bake at 350 degrees for 15 minutes. Roll in powdered sugar while still warm.