For the roulades, wash the tomatoes and celery. Peel carrots and onions. Cut everything into fine cubes. Dab cucumber cubes dry if necessary and mix with approx. 1⁄3 onion cubes. Dab roulades dry and season with salt and pepper. Spread 1⁄2 tbsp. tomato paste on each. Cover each with 1 slice of ham and sprinkle with the cucumber mixture. Roll up the roulades and pin them.
Heat clarified butter in a roasting pan. Fry the roulades in it until they are well browned all around. Add 1 tbsp. tomato paste, half of the vegetables and half of the remaining onion cubes and fry briefly. Deglaze with wine, bring to the boil, cover and stew for about 2 hours.
For the side dishes, peel and wash the potatoes. Cover and cook in salted water for about 20 minutes. Clean and wash the beans. Cook in boiling salted water for about 10 minutes. Drain. Heat butter in the pot. Fry the remaining onions until translucent. Swivel the beans in it.
Take roulades out of the roaster. Pass the braising stock and vegetables through a sieve and, if necessary, top up with water at 1⁄2 l. Bring to the boil in the roaster with the remaining vegetable cubes. Stir the starch and 4 tablespoons of water until smooth and thicken the stock. Season the sauce with salt and pepper. Heat the roulades in the sauce.
Drain the potatoes. Add milk and mash everything finely. Stir in pesto. Serve everything.