find a professional cook book. these books teach you how to calculate recipes and scale them (even in relation to whether something is a side dish or mains, they also include tips on calculating waste/trimmings and what to do with them). check your local library. i think there is a starter course from the culinary institute of America, in German there is “der junge Koch”

absolutely! these all work very nice with naga chillis, either dried or with a homemade “sauce”. i usually make a sofrito (i.e. no vinegar, no sugar, little salt, just sauteed veggies with maybe an apple) with lots of chillis. it really brings out the fruitiness. but it spoils fast so either can it or keep it in the freezer/fridge.

anything with beans/lentils really. i like Pasulj, Turkish lentil soup, and ful medame. these are all easy to prepare, cheap, and filling. you can also deviate from standard recipes by throwing other veggies into the mix (within reason). they also work very well with some soft boiled eggs and hot sauce.