Lemon Sponge Pie I

Step 1
Preheat oven to 375 degrees F (190 degrees C).

Step 2
In a large bowl cream together the butter and sugar until light and fluffy.

Step 3
Beat the egg yolks, flour, salt, milk, grated zest, and lemon juice into the creamed mixture.

Step 4
In a clean bowl and with clean beaters, beat the egg whites until stiff but not dry. Fold the egg whites into the filling. Pour into the unbaked pie shell.

Step 5
Bake for 15 minutes. Reduce the temperature to 300 degrees F (150 degrees C), and bake for an additional 45 minutes or until the top is golden and a toothpick inserted in the center comes out clean.