Things to add to meals to replace the flavour of onion and garlic in recipes, because I really do benefit from avoiding those substances! At the moment I'm using cumin, coriander, paprika and liquid smoke, but other ideas would be fantastic.
Wow, I cant imagine a world without garlic and onion, it makes me shed a tear thinking about it. I'm actually going to get a tattoo of a knob of garlic THATS how much I love it. To answer your question, I guess you're looking for pungent replacements, depending on the recipe you could use a teaspoon of white miso paste, sumac is a lemony tasting middle eastern spice, dukkah another middle eastern spice/seed mix full of earthy strong flavours. Other things I could think of that have tangy pungent tastes are reduced balsamic vinegar and if you can find it truffle oil (white or black) is magic. Its truly worth the $30 or so a bottle, you only use a little bit. Also maybe try some different salts, like black salt or pink salt!
What do you consider a hearty vegetable? I find it hard to have a vegetarian meal which keeps me full for more than an hour or so.
It's the old protein and carbs answer. The traditional meat and potatoes is the carbs from the potatoes fills you up now and the meat keeps you full later. So when making your meals consider if you have enough direct sources of protein in it. Potatoes in your soup will fill you up for that first hour but think about adding some cubed firm tofu, think of it like little sausage pieces you would add to a minestrone. Buy the firm tofu that's like a big block of cheese, open and put into a bowl of water and run some water over it for a few minutes then pat down the tofu with some paper towel. If you have time or can be bothered put a bunch of paper towel down then the tofu then more paper towel on top and then a plate and weigh down the plate with some cans or something to slowly squeeze the water out. Cube and throw into your soup, or stir fry or pasta sauce. Beans are also a good source of protein, throw some chickpeas or butter beans or kidney beans into your salad/soup/pasta sauce. Consider reading up on low GI foods as well, these are slow burn carbs that keep you feeling full for longer.