Peel the onion, dice it into small pieces. Halve the peppers lengthways, remove the core and cut into very small cubes. Dice only the firm flesh of the tomatoes. Core the paprika and cut into small cubes. Peel the carrots and kohlrabi, clean the fennel and cut all 3 into small cubes. Finely chop the parsley. Crumble the sheep's cheese a little. Peel the potatoes, cut into approx. 5 mm thin slices and cook them in salted water until cooked (approx. 5 - 6 min. Depending on the type of potato), drain, have them ready. For the crispy crumbs, melt the butter and mix with the panko flour to make crumbs.
Heat the oil in a large pan, fry the onions and diced pepperoni until translucent and then add the meat. When it is well seared, add the diced carrots, kohlrabi and fennel and let everything stew for 2 minutes. Fold in the tomatoes and diced paprika, season everything well, pour in the stock and simmer over a medium heat for 15 minutes. Fold in the crème fraîche and chopped parsley and let everything simmer for another 10 minutes.
Preheat the oven to 220 ° O / bottom heat. Butter a 20 x 30 casserole dish well and sprinkle with breadcrumbs. As a first layer, place a layer of potato slices in the mold, spread half of the minced vegetable mixture on top, sprinkle half of the sheep's cheese on top, another layer of potatoes, the second half of the minced mixture and the rest of the sheep's cheese and finally the remaining potato slices. If these no longer completely cover the minced mass, that is OK. Then sprinkle the crispy crumbs over the top and slide the pan into the oven on the second rail from below. After 20 minutes, spread a few more flakes of butter on the surface and put the pan back in the oven for another 10 minutes. The crumbs should be golden brown and crispy.
Meanwhile, grate the Belper tuber coarsely and sprinkle it over the hot crumbs just before serving. This gives the "leftover dish" a little "flavor kick". But now you don't always have a Belper Knolle on hand (it has been in the fridge for some time), so you can also work with another, spicy hard cheese that should not be baked, but only serves as an aromatic finish.
This dish is not meant to be a casserole, which means it disintegrates when you lift it out of the mold. But that's intentional, because a "G'röst'l" is actually a pan dish that can be made from a lot of things that are left over or have to go. The oven variant is just a little easier and you can prepare the dish well and only put it in the oven later. In addition, you get the crunch from the crispy crust without having to prepare it in a pan. The recipe given here is only a guide to the ingredients and can be changed as required. A fresh, mixed leaf salad is perfect as a side dish.