French Apple Tart

PEEL, QUARTER and core the apples. Slice 3 apples into thin slices, toss with lemon juice and 2 tablespoons of the sugar and set aside. Make applesauce with the rest of the apples: Chop coarsely, place in a saucepan with 2-3 tablespoons of water, cover and cook over a medium-low heat until very soft. Warm the jam, then force it through a sieve (fruit bits can be returned to the jar). Add 1/4 cup of strained jam to applesauce, together with the Calvados and butter. Continue cooking, if needed, until fairly thick. Taste and add sugar if needed. It should