Cook until puree is obtained. If the apples are ready, but have not turned into mashed potatoes, you can punch with a blender. Add starch, three yolks and vanilla to the apples. Cook the cream on low heat for about three minutes. As soon as the cream brightens and increases in volume, remove from the stove, cool. Whisk the softened butter into a fluffy foam. Add the apple cream parts, beat with a mixer until smooth.