Brazo de Mercedes

Ingredients
10 eggs, separate yolks from whites
1 1/4 cup sugar
1 tsp cream of tartar
1 teaspoon vanilla extract
1/2 cup condensed milk
1/2 cup evaporated milk
1/2 teaspoon lemon
 
Preparation
Beat the eggwhites with the cream of tartar untill stiff. Stir in the vanilla extract. Add the sugar gradually and beat untill smooth.
Line a jelly roll baking pan with wax paper and [...]