1/2 c. sugar
1/2 c. brown sugar
3 tbsp. cocoa
2 tbsp. flour
1/8 tsp. salt
2/3 c. milk
2 tbsp. light corn syrup
1 tbsp. butter
1/2 tsp. vanilla

Combine first 5 ingredients. Stir in rest of ingredients, but vanilla and cook until it boils. Continue cooking until desired thickness. Stir in vanilla.