Tomatoes have a window of ripeness rivaled only by avocados, which is problematic if you tend to buy in bulk. It helps to have a “use ‘em all up real quick” backup plan - which is where this recipe comes in.
Try as you might to avoid it, you will — at some point — find yourself with either too many tomatoes, some bland, flavourless tomatoes, or too many bland, flavourless tomatoes. The solution, my friends, is to make pasta sauce.
Enter my friend Amanda, who decided to grow a metric buttload of tomatoes this summer. Her solution to this “problem” of abundance was an elegant one: use a slow cooker to pressure-peel the fruit, then —using the slow cook setting — concentrate the umami-packed goodness by evaporating the excess water.
You will need a food mill, but the only ingredients you’ll need are tomatoes, some sort of liquid to bring the pot to pressure (I used wine), and maybe a big pinch of salt. It’s so simple, it barely counts as a recipe, but I’m happy to walk you through the process.
First, grab any and all tomatoes you have, wash ‘em, and put them in the insert of your slow cooker or Instant Pot. Do not remove the stems (some say they add an herby note). Do not core them. Definitely don’t seed them. Add a cup of your favourite liquid. This can be water or wine, but stay away from anything with a higher proof, as liquor can create an ignitable vapour cloud, which is bad.
Close the pot, select the pressure cooking setting and select a cook time of around three minutes. Once that time has elapsed, let the pressure release naturally, then open the cooker and transfer its contents to a big bowl.
Next, grab your food mill, and start squishing and milling the tomatoes back into the pot. At first you will be like “um, this is just tomato juice,” but do not fret. Keep going, milling those juicy bois until all you have left is stems, seeds and skins. Don’t throw these out: Mix them with an equal mass of salt and dry them out in the oven to make tomato salt. (See the full process here.)
If you're using an Instant Pot, leave the lid off, press the “Slow Cook” button, and use the “Adjust” button to make sure it’s set to “Normal.” Let the sauce cook and condense for 15 hours, stirring every once in a while if you feel like it. I stirred maybe a total of three times during the cooking period, more for my benefit than the sauce’s. The process is more or less the same for a regular slow cooker.
The above method will give you about a litre and a half or very saucy sauce. I like to keep mine fairly loose, so I can cook it further with other ingredients and not worry about it getting too thick. If you want yours thicker, just cook it longer.
If you want tomato paste, let it go for another 15 hours. Once you have reached your desired sauce consistency, spoon or decant it into jars or soup containers, and get it into the fridge or freezer. Repeat as needed until your tomato supply is depleted, making sure to take a tomato sandwich break every once in a while.