My proteins tend to be stuff like nuts, tofu, fish, eggs, and beans.
My starches are usually whole wheat pasta, brown rice, or some kind of bread, but YMMV, I spent a year using couscous because it's a lot faster than rice.
I also like potatoes. Yes.
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My veggies are... whatever's in season, augmented by onions and occasionally something like bell peppers or organic carrots if they look really good in the store. (I don't buy organic everything, we don't have that kind of budget, but there are some foods where the difference between organic and non-organic is palpable and carrots are one of the most dramatic examples.)
(aside: I always make sure we have powdered garlic, because fresh garlic isn't always available but when it is, ooooh boy yes please especially if it's organic. My aunt taught me "Provided it is fresh, one can never use too much garlic.")
My default meal plan is to grab a protein and a veggie and stir-fry them with onion, garlic, soy sauce and ginger, and put them on top of a starch.
Sometimes I add a can of tomato paste and it's a pasta sauce! Sometimes I fry potatoes and it's a hash! Maybe I use honey and orange juice and apple cider vinegar and make it kinda teriyaki-ish on top of rice!
The other default is roasting. Chop up all your veggies and potatoes into finger-food chunks or slice, toss them in oil with flour and spices (I often just use off-the-shelf curry powder from an Indian store), then spread them out on a tray and bake 'em at maybe 350F for 45 to 60 minutes.
It's a good response to "these root veggies are going to spoil before we can eat them!"
Because now they're snackables.
Often I Google the food we've got that needs to be used up before it spoils, and read several different recipes as inspiration for the kinds of tastes and techniques to use.
Like, for tonight, the reason I added peanut butter was because I wanted something reminiscent of pancit. A common denominator in taste for many pancit recipes is soy sauce and peanut oil.
I didn't have peanut oil so I threw in a glob of peanut butter.
The single most useful cooking resource I've ever had (aside from actual people working alongside me) is my mother's old battered copy of
Tassajara Cooking by Edward Espe Brown. It's a great cookbook (rather than recipe book) which goes through lots of basic ingredients and generalisations, then goes by kinds of food (soup, dressing, casserole, etc) and lays out the concept and principles of that kind of food before giving examples.
So Edward will say "thin soups are this, thick soups are that, you'll need something from each of these categories (with examples), and here are how some soups you're familiar with break down into this pattern." That means I can think "I want to make soup" and see what I've got in the cupboard that will go into a soup, OR I can look at my available ingredients and say "That looks like a soup."