Peel and finely dice the onion and garlic. Heat the oil in a pot. Sauté onion and garlic in it. Stir in the tomato paste, sweat it on and deglaze with tomatoes. Bring to the boil, puree finely and season to taste with salt, pepper and sugar.
Simmer covered for 3-4 minutes. Wash parsley, dab dry, pluck leaves from the stalks and chop. Drain the artichokes and cut into slices. Wash lemon hot, grate dry and tear off zest.
Add the artichokes, lemon zests and parsley to the sauce, continue cooking for about 1 minute and serve in a sauce boat.