For the sweet jackfruit dumplings, first drain the canned jackfruit pieces through a sieve, rinse well with cold water, drain and place on a piece of kitchen paper to dry.
Boil the potatoffeln in their skins in salted water for about 20 minutes (depending on the size of the potatoffeln) until tender, drain the water, allow the potatoffeln to steam briefly, peel off the skin and press the peeled potatoffeln through the potatoffeln press into a large bowl while still hot.
Put the flour on a clean work surface, spread on it the potato mixture with margarine, cornmeal, lemon zest, salt and the hazelnuts. Knead the ingredients into a dough, form it into a roll about 5 centimeters in diameter and cut it into 12 pieces. (Put breadcrumbs on the work surface to prevent the dough from sticking to your fingers). Press the jackfruit into the 12 potato dough pieces and form them into dumplings. Put the dumplings in boiling salted water and let them steep in it for about 20 minutes.
In the meantime, melt the margarine in a frying pan. Mix the breadcrumbs with panko flour, add to the pan and lightly toast over medium heat. Lift the finished sweet jackfruit dumplings out of the water with a skimming löffel, drain and carefully roll in the toasted breadcrumbs.