Defrost the strudel dough. In the meantime, peel and chop the onions. Finely dice the bacon. Leave it crispy in hot oil. Fry the onions briefly. Mix bacon, onions and sauerkraut.
Season with salt, pepper and caraway seeds and let it stand for about 10 minutes. Unfold dough sheets. Brush each sheet with a little melted butter and lay them on a tea towel so that the sheet measures approx. 40 x 30 cm.
Spread the sauerkraut over it. Roll up firmly with the help of the cloth. Cut into approx. 8 thick slices and place in a greased casserole or springform pan (approx. 26 cm Ø). Heat the stock and pour into the mould.
Cover and cook in the preheated oven (electric: 175 °C/ gas: level 2) for 20 minutes. Then finish cooking for 15 minutes without foil. Serve garnished with parsley.