Using carrots and celery in the sauce for lasagna........Is this a boomer thing? Tomato sauce doesn't need carrots and celery in it, especially not for homemade lasagna. If you don't want to use processed sugar, just use a tiny hit of molasses to add sweetness. It'll add the sweetness, without ruining the sauce with needless extra veg. of course. the addition of sweetness from a vegetable is always better than a processed one. You can also steam/boil the carrots first so they dissolve in the sauce, so you aren't left with chunks of parsnips/carrots in your sauce.