Steam the margarine and onion rings for about 5 minutes until the onions are almost soft. Add a dash of wine vinegar and keep stirring until the liquid has evaporated. Stir the 2 cups of creme fraiche into the onions and simmer for another 5 minutes. Mix in 8-10 teaspoons of mustard, season with salt, pepper and a pinch of sugar.
Season the pork fillet with salt and pepper. Wrap the bacon around the meat. Then place the ham and meat parcels in a greased baking dish. Spread the onion and mustard mixture on top.
Baked in the oven at approx. 200 ° C for 40-45 minutes.