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400°F / 205°C, cut faces up, one uncrowded layer, garlic pulled at 25 minutes

tomatoes + whole garlic head + 2 tbsp of the olive oil, until the tomato skins have blistered and blackened in patches and the halves have visibly slumped and given up their water. This is a concentration step: a raw tomato is ninety-odd percent water and would thin the sauce to soup, and the browning at the blistered edges is flavour that cannot be got any other way. Pull the garlic well before the tomatoes — it is soft and sweet at twenty-five minutes and acrid by forty, and burnt garlic is not something the rest of the sauce can outvote. Crowding the pan is the failure here: tomatoes packed tight steam in their own liquid and never blister.