Peel the potatoes, pre-cook them until al dente and cut into slices. Wash the meat and pat dry.
Cut the hare fillets into pieces of the same size (about 5 cm). Cover with sage leaves. Halve the ham slices, lay them flat on the pieces of meat and fix each with a toothpick. Preheat the oven to 100 ° C.
Fry the fillets on the side without the ham in 1 tablespoon butter. Turn briefly, toast briefly on the ham side, and season with salt and pepper while roasting. Take the meat out of the pan, put it in a casserole dish lightly greased with butter, this time turn the ham on top and place in the oven for 20-25 minutes at 100 ° C, or shorter if you like.
Extensively deglaze the roast set with white wine, bring to the boil and reduce to taste, bind with 1 tablespoon cold butter and keep warm.
While the fillet pieces are ripening in the oven, fry the potatoes with the chopped onion in a pan with pepper, salt, paprika and cumin. Arrange the fried potatoes and fillets on a plate, drizzle the sauce (unfortunately it won`t be that much) over it and serve.