Peel, wash and roughly dice the carrot. Peel onions. Chop 2 onions roughly, cut 2 into strips. Cut bacon crosswise into strips. Cut cucumbers lengthwise into quarters.
Dab roulades dry and season with salt and pepper. Spread with 1 tsp. mustard on each. Cover roulade slices on one side with strips of bacon, cucumber and onion. Roll up and pin.
Heat the lard in a roaster. Fry the roulades in it for about 10 minutes until they are brown all around. Remove. Fry the carrot and onion cubes in the frying fat. Stir in the tomato paste and sauté briefly.
Deglaze with 3/4 l water and bring to the boil. Put the roulades back into the roaster. Cover and stew for about 1 1/2 hours.
Meanwhile cover frozen beans and cook in boiling salted water for about 8 minutes.
Lift the roulades out of the stock and remove the roulade needles. Pour the stock through a fine sieve into a pot and bring to the boil. Stir starch and 4 tbsp. water until smooth. Stir into the boiling stock and simmer for 1-2 minutes.
Season with salt, pepper and 1 pinch of sugar. Place the roulades in the sauce.
Drain the beans. Put them back into the pot with butter and toss. Season to taste with salt and pepper. Serve with the roulades. Boiled potatoes go well with it.