When you slather plain yogurt on the bottom of a plate or shallow bowl and season it with salt and pepper, it becomes a creamy base for whatever you have in the fridge: a handful of arugula, a spoonful of white beans, and the meat you pulled off a leftover chicken leg, for example. Or some cubed sweet potato, a can of chickpeas, and some cold cooked greens.
Start with 1 cup plain Greek yogurt. Whip it with a fork or whisk to lighten it up, then season it with a little kosher salt and, if you feel like it, a finely chopped garlic clove. Spread the yogurt on a plate or on the bottom of a shallow bowl and top it with whatever’s in the fridge: leftover cooked vegetables like squash, mushrooms, or broccoli; tomatoes in any form (sliced grape tomatoes, leftover tomato sauce); warmed leftover sausage or meatballs; boiled eggs and tinned fish like tuna and sardines; cooked or canned chickpeas or black beans or cooked grains like quinoa; pickle-y things like olives, capers, and pepperoncini; almost any dried or fresh herb, such as thyme, basil, parsley, mint, or oregano; and anything crunchy, such as toasted nuts and/or seeds, or crunchy raw vegetables like celery. Finally, finish the bowl with a sauce. A green sauce (here), vinaigrette (here), or hot sauce are all nice, but so is a simple drizzle of lemon juice and olive oil.