Immerse the tomatoes in boiling water for about 30 seconds and chill immediately. Then remove the skin and seeds. Quarter to eighth, depending on the size.
Gently sweat the shallot and clove of garlic with the thyme in the olive oil in a sauté pan or saucepan until translucent. Add the tomatoes and simmer for 30 minutes until the juice is completely reduced.
Remove the thyme and season with salt, pepper and a pinch of sugar and fold in the basil if you like. Tomato concassé goes well with Mediterranean meat and fish dishes.