INGREDIENTS & SUPPLIES

• Tomatoes – any variety can be used!
• Olive oil, for drizzling (but do NOT use any oil if you intend to hot-bath can this recipe)
• Sea salt
• Black pepper
• Baking or roasting pan
• Large pot
• Blender – we use an immersion blender (aka stick blender) for this recipe 
• Optional: parchment paper 

INSTRUCTIONS

Step 1: Prepare & Season Tomatoes

Preheat the oven to 425°F

Wash those ‘maters, and get to choppin’! The other beautiful thing about this recipe is that because everything is going to get cooked and blended, size and shape doesn’t matter much here – nor do we need to worry about removing the skins! We also leave the seeds and guts, which enhances the caramelization process.

Cut away the firm stem center (if there is one), and then portion your tomatoes into large chunks. We typically cut the smaller tomatoes in half, and larger ones into quarters or sixths. You can totally leave cherry tomatoes whole! 

On a baking sheet, lay out all the tomato pieces – skin-side down if possible. Lining the baking sheet with parchment paper makes for a much easier clean-up, since the tomato juices tend to stick and crust to the pan while roasting. It is okay to pack the tomatoes in there, but try to keep them in a single layer.

If you find you have more tomatoes than can fit on your pans for the oven, but want to process and preserve them all, check out optional Step 3! 

Now, drizzle the tomatoes with olive oil, and give them a sprinkle of sea salt and black pepper. Again, omit the olive oil if you wish to can your sauce.

Step 2: Roast the TomatoesHere is where the magic happens. 

When exposed to high and dry heat, foods take on a whole new complex flavor profile because of the chemical reactions that take place. Namely, caramelization.

According to the Science of Cooking, caramelization is an oxidative reaction that involves the removal of water (as steam) and the breakdown of the sugar. As the the browning process occurs, natural volatile chemicals are released that produce the characteristic caramel flavor.  Thus, roasting vegetables can transform their earthy, vegetal, sometimes slightly bitter taste into something sweet, nutty, and toasted instead!

Roast the tomatoes in the oven on 425°F for approximately 35 to 45 minutes, until they become soft and lightly browned – or even a tad blackened, like ours! If you’re working with multiple trays of tomatoes, it may take a little longer (up to an hour). Rotate the trays halfway through to promote even roasting. 

Step 3: Stew Other Tomatoes (Optional)

For the batch of sauce we made in this example, we filled two cookie sheets and one large glass roasting pan with tomatoes. The oven was full, but we still had a lot left on the counter! Rather than roasting all the tomatoes in multiple batches (no time for that!) we opt to simply not roast some at all. Instead, we stew the left over tomatoes – and combined them with the roasted ones when they came out of the oven. The flavor is still phenomenal. If you’re in the same situation, try this option!

While the initial trays of tomatoes are roasting in the oven, process any leftovers. Prepare them in a similar fashion as the others: cut away any tough stem portion, and chop them into a few chunks each. Heat a large pot on the stovetop, and add a splash of olive oil followed by the extra tomatoes. Lightly simmer the tomatoes (uncovered) the entire time the others are in the oven – at least 30 minutes. Stir occasionally. They will become soft, wonderfully fragrant, and the liquid will reduce. 

Step 4: Reduce & Blend the Roasted Tomatoes

Once your tomatoes are finished roasting, you have a couple of options. If you are using a traditional blender and did not stew any additional tomatoes on the stove, you could transfer the roasted tomatoes directly to your blender. I would allow them to cool slightly first to avoid hot splatters! 

However, if you want to reduce the tomatoes even more to create an extra thick sauce (and/or if you have those other tomatoes already stewing in a pot) carefully transfer the roasted tomatoes into a pot on the stove. Heat and simmer to further reduce the chunky sauce to a thickness of your liking – but keep in mind it will become even thicker once it is blended! 

Next, blend the tomatoes until the sauce is a smooth, creamy consistency. Using a stick blender makes this extremely easy, right in the pot! We love this immersion blender, and use it regularly for many recipes – like this creamy roasted carrot and sweet potato soup! Alternatively, blend your roasted tomato sauce in a classic blender in batches as needed. You could choose to leave it chunky and not blend it at all. But keep in mind the skins will be more noticeable and potentially tough if they aren’t blended. 

After blending, assess the thickness. If you want it thicker even still, continue to simmer on medium-low heat to reduce further. Or, if it is all good to go, continue to the next step!

Step 5: Cool, Pack & Store

Now, allow that delicious, hot roasted tomato sauce to cool down a bit. When you package it into your storage containers of choice, the temperature can still be warm – but shouldn’t be hot. To promote rapid cooling, we usually create an “ice bath”, setting the pot surrounded in ice water in a clean sink. Yeah, I used to be a health inspector.

Freezing Roasted Tomato Sauce 

To preserve and freeze roasted tomato sauce sauce, we typically use pint-sized mason jars. Yes, you can safely freeze food in glass jars! However, make sure you get the ones that are marked as freezer-safe. Those are usually only the wide-mouth pint, half-pint, and quarter-pint size. Glass jars with a “shoulder” are more prone to cracking in the freezer, such as quart jars or regular mouth pints.

You can also freeze the sauce in durable BPA-free plastic containers made for the freezer, like these “Reditainer extreme freeze” pint containers or their quart-size containers. We use them all the time for soup and broth too!

Once the sauce is decently cooled, transfer it into your containers of choice. We use a canning jar funnel to help reduce the mess if we’re using glass jars. Maintain one inch of head space to allow for expansion in the freezer.  Store the containers of roasted tomato sauce in the freezer, and use within one year for the best quality and flavor. 

Canning Tomato Sauce

We prefer the ease and quickness of freezing tomatoes, but if canning is your thing, be my guest! I won’t get into detailed instructions on exactly how to can tomatoes, but here are some quick safety notes below. For more detailed canning instructions, check out this guide from Colorado State University. Similar to the freezer option, it is suggested to use canned tomatoes within one year. Only proceed with canning if you didn’t use olive oil in this recipe. Leave 1/2″ head space in jars when canning.

To ensure safe acidity in whole, crushed or juiced tomatoes, add bottled lemon juice or citric acid when processing in a boiling water bath. Thoroughly stir in 2 tablespoons of bottled lemon juice or 1/2 teaspoon of citric acid per quart of tomatoes. For pints, use 1 tablespoon bottled lemon juice or 1/4 teaspoon of citric acid.

Colorado State University