Put cream, milk, and sugar in a pot and bring to a boil. Remove the pot from the heat and stir in the instant gelatin and the chopped white chocolate. Stir the mixture so the chocolate melts. When the mixture is smooth and even, add the egg yolks. Stir until the mixture is completely smooth and pour it into a siphon bottle. Refrigerate the bottle until it is completely cold. Take the bottle out of the refrigerator about 1 hour before serving. Add 1-2 cartridges and shake well. Spray the espuma over your favorite late-summer dessert.