INGREDIENTS

1 cup unsalted butter
1 cup solid-type firm margarine
1 cup granulated sugar
3 cups all-purpose flour
1 dash salt , helps bring out flavours (optional)
1 egg , separated
1 teaspoon vanilla
1 tablespoon cold milk

DIRECTIONS

Cream the room temperature but not too soft butter and margarine together with the sugarusing awooden spoon.
Add the vanilla and unbeaten egg white only.
Add the flour until a stiff dough forms, and can be handled.
With floured hands pat into an 10 x 16 baking pan about [...]