Quick Nut Fudge

1/2 lb powdered sugar (1/2 box)
1/4 cup cocoa
1/4 teaspoon salt
3 tablespoons butter
2 tablespoons milk
1/2 tablespoon vanilla
1/2 cup chopped walnuts

1. combine all ingredients into microwave safe bowl
2. heat in microwave 2 minutes and stir until mixed
   
3. repeat as necessary until melted
4. pour into greased baking dish
5. chill until firm