One of my children is allergic to tomatoes, among other things. When you have a large family with multiple food allergies, it is easier, at least with the big meals to only include ingredients that everyone can have, rather than make several separate dishes for individuals. Years ago, when we were on the Feingold diet there was a recipe for Untomato Sauce which used beets. Beets are not my favorite. (When I was 16 I decided to go on an extreme cleanse diet which consisted of nothing but vegetable juice, specifically beet juice. all day every day for 4 days. I have never felt the same about beets since) Anyway, I am always trying to come up with substitutes for things. One day I was using butternut squash for a sauce and I thought, "Hm. If I added some cherries to this it would probably look like tomato sauce. And cherries are tart yet slightly sweet, like tomatoes." I added salt, pepper, and italian herbs such as oregano and basil to it, and voila. tomato sauce, Italian style. Don't judge until you try it. Seriously. My kids say it is very close to the real thing. If you have a kid with a tomato allergy, make this and try it. They don't have to know what's in there. I used frozen organic cherries from Costco. I cooked them down on a stovetop until there was a liquidy syrup accompaniment. About 4 cups frozen. Add to about 4 cups of cooked butternut squash, no skin. Blend well in a high powered blender. Depending on how much cherry juice you have you might want to add a little water to get the sauce nice and smooth. We have a vitamix.
Here's a printable recipe.