For the compote, cut the peeled and pitted apples into cubes and sauté in the butter. Add the sugar, deglaze with lemon and apple juice and let it boil down. Stir in a little cinnamon, take the pan off the stove and let the compote cool down.
For the crumble, put the butter in a small saucepan, let it melt and mix with the grated ginger. Add the remaining ingredients and grate into sprinkles. Chill the crumble for 30 minutes. Preheat the oven to 180 degrees top / bottom heat. Place the crumble on baking paper and bake on the middle rack for about 15 minutes, depending on the oven.
For the cream, whip the cream until creamy. Mix the sour cream together with the sugar in a small bowl, add a little grated lemon zest and a splash of lemon juice and fold in the creamy whipped cream.
Spread the sour cream on 4 dessert glasses, add the apple compote and finally the crumble.