Cream the butter, then cream in the sugar until very light. Beat in the egg yolks thoroughly. Sift the flour with the dry ingredients and add alternately to the creamed mixture with the milk and vanilla. If using an electric mixer, turn it off and lift the beater before adding the flour mixture. Turn it on to the lowest speed, add the liquid, and mix only until the batter is smooth. Spread in a greased and floured pan (or pan lined with greased paper) 8 x 10 inches or 10 x 13 inches. Beat the egg whites until foamy, add the lemon juice or cream of tartar. Slowly beat in the brown sugar and beat until stiff and smooth and the sugar is dissolved. Fold in the nutmeats (or fold in half and sprinkle the remainder over the top after spreading). Add a few drops of vanilla, if you like. Spread evenly over the cake batter. Bake in a 350°F oven about 50 minutes. Cool in the pan on a cake rack.