Wash the liver slices under running water, pat dry and turn in flour. Heat the oil in a pan and fry the garlic cloves grated with 1 teaspoon of salt, add the liver and fry for about 2 minutes on each side, remove and keep warm.
Leave the bacon in the remaining frying fat, add the onion slices, fry briefly, dust with flour, deglaze with red wine and top up with meat stock. Cover and simmer over medium heat for 10 minutes. Mix in the peeled, pitted tomatoes. Season with salt, pepper and seasoning and fold in the chopped herbs. Serve the liver slices with the sauce.