Step 1Heat the broiler.
Step 2Place the tomatoes on a baking sheet, and put them directly under the broiler. Watch them carefully: As they blister and the skins turn black, turn them over. When the skins are pretty well charred, about 3 minutes each side, remove the tomatoes from the oven, peel off the skins (they will almost fall off), and trim out their stem ends.
Step 3Cut the tomatoes into large pieces and put them back on the baking sheet. Peel the garlic cloves, cut them in half if they're very large, and scatter them among the tomatoes. Drizzle the tomatoes with 1 tablespoon of olive oil, and sprinkle them with 1 teaspoon of salt. Turn the oven down to 400 degrees and set the tomatoes on the middle rack. Check them every half hour, and as they start to show little charred spots again, stir them up, mixing the blackened spots in.
Step 4In about 1 1/2 to 2 hours, you should have a thickened mass of tomatoes, flecked with dark bits. Remove this from the oven, give it another stir, taste, and add salt only if needed.
Step 5Spoon the tomatoes into a shallow serving bowl, smooth the top, and drizzle the remaining tablespoon of olive oil on top. Remove the pits from the olives and chop the olives coarsely. Sprinkle the chopped olives over the tomatoes.