Welcome to Bake Club, Nerida! She explains this German specialty:
I fell in love with this kind of poppy-seed pie on my first visit to Germany. The poppy-seed filling is not adulterated with flour. And the crumble or streusel topping is the delicious finishing touch!

Filling:
375 ml milk
50 g butter
50 g sugar
250 g poppy seed
50 g semolina
50 g almond slivers
1 large egg
3 TB raisins soaked in rum

Heat milk, butter and sugar stirring constantly until butter is melted - almost to a boil. Mix the dry ingredients and poor the hot mixture over them. Stir and leave to cool.

Pie crust:
250 g flour
125 g butter
10 dl cold water
3 TB sugar
1/4 tsp salt

Crumble:
100 g butter
100 g flour
50 g sugar

 Mix together just until crumbly and refrigerate. 

Line the bottom of a springform with baking paper. Grease the sides well. Roll out the pie crust so that it goes about half way up the sides of the springform. Pour the filling in. Bake at 180 degrees C for about 20 min. Then spread crumble topping evenly across the top and bake for another 20 -25 minutes.