Lemon Sauce - cooking recipe

Ingredients

3/4 c. sugar
2 Tbsp. cornstarch
dash of salt
1 egg yolk
3/4 c. water
3 Tbsp. lemon juice
1 Tbsp. butter

Preparation

Mix first 6 ingredients.
Cook in a double boiler until thick, stirring constantly.
Remove from heat.
Add butter and cool.