Homemade tomato conserva bears little similarity to commercially prepared tomato paste, even the imported stuff from Italy. It is the very essence of tomato in a super-concentrated form. Just one spoonful of conserva will make a minestrone soup taste like an Italian grandmother stepped into your kitchen. To rekindle a memory of Spain, spoon a thin layer on toasted garlic bread and drizzle it with olive oil for an astounding pan con tomate. You will need what might seem like a lot of tomatoes to make two small jars of this precious condiment. Paste tomatoes, such as Roma or plum types, will give you the thickest conserva, but any vine-ripened tomatoes will work.
Ingredients
- 10 pounds ripe tomatoes
- 1 teaspoon artisanal sea salt
- Extra-virgin olive oil for pans and to top off jars
- Food mill or chinois (fine-mesh conical sieve)
- 2 (½-pint) glass jars with lids
Preparation
Cut large tomatoes into quarters, and cut medium and small tomatoes into halves. Don’t worry about stems and cores, as they will be removed later. Put all the tomatoes in a large, heavy nonreactive pot and add the salt. Place over high heat and cook, stirring frequently with a wooden spoon to ensure nothing sticks to the pot bottom, until the tomatoes boil and release their juices, about 10 minutes.
Position oven racks in the center and top third of the oven and preheat the oven to 250°F/135°C. Using food mill fitted with the fine disk or a chinois, carefully pass the hot tomatoes through the mill or sieve into a large bowl. Coat 2 large sheet pans with the olive oil, then divide the puréed tomatoes evenly between them.
Place the pans in the oven. After 1 hour, pull the pans from the oven and use a rubber spatula or, better yet, a baker’s dough scraper to fold the mixture onto itself. It is especially important to scrape the edges of the pans where the sauce will evaporate first. Return the pans to the oven. Repeat the scraping and folding every 30 minutes until the mixture has significantly reduced in volume, about 3 hours. Then combine the mixture from both pans onto a single pan and continue baking until the mixture is a glossy brick red and as thick as tomato paste. This last step should take about 3 more hours. Remove from the oven and let cool to room temperature.
Wash the jars and lids in hot, soapy water. Rinse, then immerse the jars in gently boiling water for 10 minutes. Just before filling, remove the jars from the hot water and shake off any excess. Have the lids ready.
Pack the conserva into the jars with a tablespoon, leaving ½ inch/12 millimeter headspace, and top off with a thin film of olive oil. Cap each jar with a lid and store in the refrigerator for up to 1 year.
