1 c. sugar
1/3 c. cocoa
1/3 c. flour
1/4 tsp. salt
2 c. milk
2 egg yolks
1/4 c. butter
1/2 tsp. vanilla

Mix first four ingredients. Add milk. Mix, cook, until thick. Add a little of mixture to egg yolks. Then add remaining filling. Cook 3 or 4 additional minutes. Add vanilla and butter.