My mother was a great cook and baker. She taught my sister and I her tricks. Lemon Sponge Pie is a Lancaster County, PA favorite. Mom would sell cakes,pies, sticky buns, and cookies to supplement her income. My youngest brother and I have memories of going door to door selling her baked goods. Big soft cake like sugar cookies were $.55/doz. Sticky buns were $.65/doz. Those days are gone.
Pre heat your oven to 450. Cream butter and sugar together, add egg yolks, flour,milk lemon rind and juice. Blend until smooth. At this juncture taste to see if it's lemony enough. You can always add another Tbl of lemon juice. With absolutely clean beater and clean glass or metal bowl beat the egg whites until stiff but not dry.( remember the tiniest bit of grease on the beater or in the bowl will prevent the whites from expanding and whipping properly.) Fold the whites into the batter mixture gently. Pour into your an 8 or 9" pie dish, in which you have lined with your favorite pie crust. And, yes you can use refrigerated pie crust. The world will not stop revolving if you do. Place your pie on the lowest rack in your oven. Bake at 450 for 8 minutes. ( This ensures that your bottom crust will also be baked). Turn oven down to 325 and bake for 25-30 minutes. Watch carefully. It should be golden brown to medium brown on the top. The center will puff and go down as it cools. This was always on our Easter table along with coconut cake. If your oven tends to run hot than adjust your temps by 25 degrees. It is done if a knife comes out clean after inserting into center of pie.