Carve tomatoes crosswise and blanch with boiling water. Rinse with cold water and peel the skin. Cut tomatoes into quarters, remove stalk and seeds. Cut the flesh into very small cubes.
Peel the shallot and garlic and dice very finely. Cut avocados in half lengthwise and remove the stone. Remove the flesh and cut into very small cubes. Sprinkle with lime juice immediately.
Mix with tomatoes, shallot, garlic and oil. Season with salt, pepper and Piment d'Espelette. Cover and leave to stand in the refrigerator for about 30 minutes.
Approx. 1⁄4 Fill the avocadotatar into an appetizer ring (approx. 8 cm Ø; alternatively fold rings of aluminium foil) for serving. Remove the ring carefully. Arrange 3 more tartar tarts from the rest of the tartar.
Served with: mixed salad and baguette.