Caramel Cake Filling - cooking recipe

Ingredients

1 c. sugar
2 Tbsp. margarine
1 egg yolk
1 c. milk
1 tsp. vanilla

Preparation

Put 1 cup sugar with 2 tablespoons butter into a heavy skillet. Cook over a slow fire stirring slowly until sugar is dissolved and becomes a syrup.
Into another boiler, break 1 egg yolk and beat, then add 1 cup of milk and set over low flame to heat (don't boil or it will curdle).
Add this to sugar syrup and cook until all lumps are dissolved.
Mix some flour and water together to make a thin paste and, if caramel is not thick enough to spread, add some a little at a time until it is the desired thickness.
Add vanilla and spread on cake.