Cake: Cream the sugar and butter until light and fluffy. Fold in the milk and half of the egg whites along with 1 1/2 cups of flour and the baking powder. Beat on medium until creamy and add remaining egg whites, flour and vanilla. Reserve bourbon to use after baking the layers.
Prepare 3 cake tins (shiny silver metal works best she says) by buttering the bottom, line with parchment paper (Alma''s notes used brown paper bags) and butter the paper and dust with flour. Pour batter into the pans evenly, tap the pans on the counter to release any air bubbles and bake in a preheated 350 oven for about 30 minutes. (20 minutes if using 4 pans) If you have to use two racks, use the middle and lower rotating the pans about half way through baking. The cake is done when the top springs back when touched and a toothpick inserted in the middle comes out with just a few moist crumbs attached. Let cake cool in pans for about 5 minutes and invert on wire racks to cool completely.
Spoon the bourbon over the tops of each layer allowing it to soak in.
Filling: Cream the butter with the sugar and then add the egg yolks beating until thoroughly mixed. Cook in a double boiler over simmering water stirring often until mixture is thick to coat a spoon and drops away in clumps (this tested to be around 160 degrees F). Remove the pan from the simmering water and stir in the remaining ingredients. Stir until cool enough to frost the cake tops. Use the filling between layers and on top of the sacked cake. Let set while you make the icing.
Icing: Beat egg whites until they stand a peak yet still glossy. Mix the remaining ingredients in a deep saucepan and bring to a rolling boil; cook for 1 minute. With the mixer going, gradually add the boiled mixture in a steady stream into the egg whites beating constantly. Beat until it is of frosting consistency. Spread icing around the sides and on top of the Lane Cake if desired concealing the top filling.