Whip the cream until soft peaks form. Add the lemon juice, zest and icing sugar. Refrigerate until serving.
Peel, core and chop the apples. Mix the chopped apple, water, lemon juice and sugar in a pan and simmer until the apple is soft. Add the vanilla extract and cardamom. Lightly beat the eggs with the milk. Add the flour, salt and vanilla extract and stir well. Add the cream and leave to stand for 10 minutes.
Add the eggs to the flour and, using a whisk, add the liquid a little at a time, whipping until you have a smooth batter. Stand, if possible for 30 minutes.
Lightly grease a flat, well-seasoned pan, and heat until it just begins to smoke. Pour on 2-3 table spoons of the batter. Quickly, lift from the heat and tip in several directions to spread the batter evenly over the bottom of the pan.
Cook until the batter is set on top and brown underneath. Turn and brown the other side.
Distribute the pancakes on small plates.
Sprinkle some walnuts over the pancakes.
Spoon a little compote and lemon cream next to the pancakes.