For the filling, dice the bread coarsely, grind finely in the universal chopper, then roast in a pan while turning. Coarsely grate the cheese. Cut tomatoes into strips. Peel onions. Finely dice 2 onions.
Wash the meat, dab dry and season on both sides with salt and pepper. Cover with salami, cheese, onions, breadcrumbs and tomatoes. Roll up tightly from the long side and tie with kitchen string.
Chop 2 onions roughly. Peel and roughly dice the carrots. Heat 3 tablespoons of oil in a frying pan and fry the meat for about 5 minutes, turning it well. Spread onions and carrots around the roast.
Cook in the preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see manufacturer) for approx. 40 minutes. Core temperature should be approx. 65 ° C.
Meanwhile pour capers into a sieve. Peel the garlic. Wash herbs, shake dry and pluck leaves from the stalks. Wash lemon hot, grate dry, grate peel thinly. Halve the fruit and squeeze the juice.
Finely chop capers, garlic, herbs and anchovy fillets. Mix with 6 tablespoons of oil, lemon juice and peel, season to taste with salt and pepper.
Remove the finished roast from the oven, wrap in foil and let it rest for about 10 minutes. Dissolve the roast with 400 ml water. Pour through a sieve into a pot. Season with vegetable stock, salt and pepper.
Stir starch and 3 tablespoons of water until smooth. Bring the sauce to the boil and thicken with mixed starch. Cut the roast open and add the sauce and salsa.