1.
Preheat the oven to 180 C / Gas mark 4. Grease and flour a 25x35cm swiss roll tin.
2.
In a large bowl, beat the eggs and egg yolks using an electric mixer. Add sugar, and beat until thick and pale, about 10 minutes. If you have a stand mixer, use the whisk attachment. Sift the flour and baking powder into the egg mixture, and fold in by hand along with the milk. Stir just until the batter is mixed. Spread the batter evenly in the prepared tin.
3.
Bake for 12 to 15 minutes in the preheated oven, or until a skewer inserted into the centre comes out clean. When finished, invert the cake pan onto a sheet of greaseproof paper, and cool completely. This will give you nice even petits fours.
4.
Cut the cooled cake into small squares, rectangles or triangles, and arrange the pieces in rows on a wire rack or glazing screen with plenty of space between rows. Set the rack over a shallow tin or greaseproof paper to catch the drips.
5.
Spoon or pour warmed petits fours icing over the small cakes. The drippings may be scraped off of the tin or paper, and reheated for use again. Allow the petits fours to set until completely dry. Lift the cakes from the rack with a metal spatula, and trim the bottom edges with a sharp knife. Set into small petits fours cases for easy handling. Decorate as desired.