Granny's apple cake

My granny died recently. She was famed for this apple cake of hers.

250g butter
200g plain flour
100g sugar (or less, to taste)
vanilla (sugar or essence)
1 egg
1 tsp baking powder
1 kg apples, skinned, cored and sliced

make a shortcrust pastry. (If veganising, use margarine, leave out egg. Margarine should make the dough moist enough, but if in doubt, add a few spoonful of cold water). Chill dough.
Prepare apples while dough is chilling.
Grease a springform cake tin or tarte form. Press most of dough into form. Arrange apples on dough, generously. Tear pieces of leftover dough over apples. Sprinkle with a little sugar and sliced almonds if you like.
Bake at 200 degrees for about 1 hours.
Absolutely serve with whipped cream, or custard if you must.