Peel, core, halve and cut the apples into large pieces. Put in a baking dish and mix with 2 tablespoons of the sugar and the grated lemon zest. Sprinkle 40 g of the butter in flakes on top.
Knead the remaining butter into the flour, add the rest of the sugar and cinnamon and work well into crumble. If you like large sprinkles, you can now add 1-2 tablespoons of water.
Pour the streusel over the apples.
Bake at 180 degrees for about 60-75 minutes, until the crust is golden brown and the juice bubbles around the edges
Serve with creme double, whipped cream or vanilla ice cream.