Bring milk, sugar, butter, honey, cinnamon and lemon peel, in a pot to boil.
Add poppy seed and rum and stir.
Cook for about 2 minutes constantly stirring.
Leave to cool.
Mix flour and baking powder.
Add butter in small pieces and crumble.
Add sugar, egg yolk, sour cream, salt and knead to a dough.
Place in fridge.
When the filling is cold, take the dough from the fridge.
Divide dough in half.
Roll out on floured surface (about 35 x 35cm)
Spread half of filling on the dough.
Roll to a strudel and put on baking tray with baking paper.
Same procedure with second half.
Brush strudel with yolk-milk-mix and pick holes with a fork.
Bake in preheated oven at 180°C for about 35 to 40 minutes.