I've found that blending up sunroots with tomato sauces and/or soups makes them pretty tasty! Additionally, it helps to thicken them and add nutrients.
You can make an excellent ketchup and cocktail sauce substitute by doing this:
• Blend up a jar of home-canned stewed tomatoes (skins, seeds, juice, and all, if you like; they all turn into sauce).
• Blend several whole sunroots into them. (If you bake the sunroots well before blending them, it adds an additional pitentially desirable flavor.)
• Add distilled white vinegar and salt (as you would with ketchup).
Then it's ready! Four ingredients. That's it. I find that I use more of it with my food than I use ketchup.
By itself, it's unique, although an excellent dipping sauce, similar to ketchup and cocktail sauce (you probably want more salt and vinegar to get a steonger cocktail-type flavor). If you add mustard to it, it tastes just like ketchup with mustard in it, except it has an earthy aftertaste (which I personally like).
Adding sunroots to tomato soup adds a substance to the flavor, similar probably to what broth does to tomato soup.
I imagine all kinds of recipes could utilize sunroots to make a large variety of awesome new sauces.
Sunroots (including both raw and baked sunroots) blend up very easily in a blender with stewed tomatoes.
I've tested this with spring-harvested sunroots, so far. These seem to be firmer when cooked, sweeter (a lot like carrots), and have less inulin than fall-harvested sunroots. They taste like a mix between potatoes and carrots. The fall ones seem to taste more like a mix between already salted and buttered baked potatoes, steamed cauliflower, and seafood; I haven't tried those in sauce, yet.
Anyway, I've tried the sauce with mustard with hamurgers (I dipped them instead of spreading it on). I tried it without mustard with meatloaf patties (which patties included tomatoes, but no ketchup), and it was excellent!