1 egg
1 teaspoon lemon juice
1 cup all-purpose flour
1 1/3 cups milk
5 tablespoons butter
2 1/3 cups emulsion
In a large bowl, mix egg, lemon juice and flour. Add milk by tablespoon and beat with the whisk until blended. Fold in butter, and beat until pale. Cover bowl and refrigerate about 1 hour.
Preheat the oven to 350 degrees F (175 degrees C).
Pour the batter into a greased 16x20 inch glass baking pan. Bake in preheated oven 15 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let cool completely before cutting into 1 inch squares.