Rinse meat and pat dry. Spread with 2 tablespoons of mustard. Peel and halve 1 onion and cut into strips. Cut gherkins lengthwise into 4 slices. Place 2 slices of gherkin on each roulade, spread onion strips on top.
Place a slice of bacon on each. Roll up firmly from the short side and pin it with toothpicks or roulade needles. Peel 1 onion and cut into pieces. Heat the oil in a casserole, fry the roulades thoroughly all around.
Remove, sauté onion, deglaze with stock and red wine, stir in 2 tablespoons of mustard. Add the roulades again, braise for approx. 35 minutes in a closed pot. In the meantime, clean and wash the Brussels sprouts and cook in boiling salted water for the last 15 minutes.
Melt the fat and fry the breadcrumbs in it. Remove the roulades and keep warm. Pass the sauce through a sieve, thicken slightly with sauce thickener. Bring to the boil again and season to taste with mustard, salt and pepper.
Drain the brussels sprouts and mix with the crumbs. Serve roulades with sprouts and sauce. Garnish with parsley. Boiled potatoes tossed in parsley butter taste great with it.