It is very hard to incorporate air into milk and to make it permanent. We tried many different approaches, and finally what worked was a combination of ingredients that help create and trap air bubbles through agitation: gelatin, soy lecithin powder and egg white powder. We also added some sugar, but what was also crucial was to use skim milk, since fat would inhibit aeration. The milk foam is assembled as a layered cake, where the sponge cake is a milk based genoise, cooked in a microwave for maximum expansion. This is the "slice of milk" we serve with a glass of cake.