Quick Glance 50 M 6 H Makes about 1 pint. http://leitesculinaria.com/87323/recipes-homemade-tomato-paste-conserva-di-pomodori.html
INGREDIENTS
10 pounds very ripe plum or salad tomatoes
1/4 cup kosher salt
1 tablespoon extra-virgin olive oil for the baking sheet, plus more for topping off the jar
DIRECTIONS
Core the tomatoes. If they are the plum type, cut them in half lengthwise; if they are the large, round salad type, cut them in quarters.
Remove the seeds with your fingers.
Place all the tomatoes in an 8-quart stainless steel pot and bring to a boil, stirring occasionally until the tomatoes release their juice.
Boil briskly for 30 minutes to soften the tomatoes and reduce the juice.
Pass the tomatoes through a food mill fitted with a fine disk to remove the skins and any remaining seeds.
Return the tomato purée to the same pot and set over high heat.
Stir in the salt, reduce the heat to medium-ish, and simmer until the purée has reduced to about 1 quart (4 cups), 45 to 55 minutes.
Turn the heat down as the purée thickens to prevent it from bubbling and splattering furiously, and stir often to prevent scorching.
Lightly oil a 12-by-17-inch rimmed non-aluminum baking sheet.
With a rubber spatula, spread the thick tomato purée in an even layer. It should cover the slicked baking sheet.
Preheat the oven to 200ºF (93ºC) and turn on the convection fan if you have one. Position a rack in the center.
Place the baking sheet in the oven and bake for 30 minutes.
Remove from the heat (keep the oven on) and stir the purée with the rubber spatula so that it dries evenly and doesn’t form a crust.
Re-spread the purée with the spatula into a rectangle about 1/8 inch thick.
Be fanatical about spreading it evenly; if any part is too thin, it may burn.
Because of evaporation, the purée will no longer cover the baking sheet.
With a paper towel, remove any bits of tomato that cling to the edges or exposed bottom of the baking sheet, or they will burn.
Return the baking sheet to the oven and continue baking until the tomato purée is no longer saucelike but very thick, stiff, and a little sticky, about 3 more hours total.
Every 20 minutes, stir and carefully re-spread the purée as before.
The rectangle will become progressively smaller as the remaining water evaporates.
Let the tomato paste cool to room temperature, then pack it tightly in a clean jar with a spoon, tamping it down to make sure there are no air pockets.
Level the surface with the back of the spoon. Cover the surface completely with olive oil so that the paste is not exposed.
Screw the lid on the jar and refrigerate.
After every use, level the surface of the paste and top with more oil so the paste remains completely submerged. It will keep in the refrigerator for at least a year.
SUN-DRIED TOMATO PASTE VARIATION
If you know you will have 3 to 4 consecutive days of 100ºF (38ºC) weather, you can dry the tomato purée under the sun instead of in the convection oven. Follow the recipe in every other respect, and start to use the sun at step 4. Be sure to bring the tray in at night so it doesn’t get damp.