For red onions, I often substitute shallots as well. But for onions in general, I do just deal with the leftovers. I will often saute it with garlic, whether the recipe calls for it or not, just to use up whatever may be left over. If I’m roasting anything, I’ll put leftover chunks next to whatever I’m roasting too for added flavor or aroma. Stock is great! If you find yourself making stock out of leftover chicken or other bits, I will throw it in too.
In the summer time, I will bury some vegetable scraps in my garden to give some extra nutrients to the soil.
