The recipe I used was a Lady Cake (a white cake with lemon and almond flavouring) from the Joy of Cooking. It was a dense but moist cake similar to a lemon pound cake. I baked them in muffin tins filling them only half way but I would recommend if you have the time to bake a sheet cake and use a cutter to cut out the cakes so that they're more level.
3 1/2 cups cake flour
1 tablespoon and 1 teaspoon baking powder
1/2 teaspoon salt
1 cup milk (not specified but I used 2%)
1 teaspoon almond extract
grated zest of 2 lemons
1 1/2 cups of butter (3 sticks)
1 2/3 cups sugar
6 egg whites
3/8 teaspoon of cream of tartar
additional 1/3 cups sugar
Sift together the flour, baking powder and salt.
In a separate bowl (I just used the liquid measuring cup) mix together the milk and flavourings. I decided to keep the zest separate until I added the milk mixture to the butter mixture but at this time grate the lemon.
Beat butter on high until creamy: 30 sec. Gradually add the sugar while beating on high until its lightened in colour. Next add the flour in three parts, alternating with the milk mixture in two parts (at this time I added the lemon) and beat until completely mixed. This recipe makes a heavier batter and it will be really thick at this point but once you add the egg whites it will get a little lighter.
In another bowl beat egg whites and cream of tartar until soft peaks form. Then gradually add the sugar and beat until the peaks stiffen without becoming dry. Despite making this recipe many times, this time around my egg whites didn't really form peaks and I over beat them to the point that it went flat again. If this happens don't worry it shouldn't affect the recipe in the end.
Finally fold in the egg whites with the batter and bake at 375. The petit fours in the muffin tins took about 15 min. and the thin cake layer we made was about 20.
3 cups icing sugar
2 teaspoons softened butter
8 - 12 teaspoons of butter
Add icing sugar and butter in a bowl. Add milk as needed and mix until a think paste is made. Heat in a microwave until warm and smooth (I did so for 40 sec.).
Dip petit fours in the glaze and sit on a rack to let the excess drip down. I laid a sheet of wax paper underneath to catch the icing.