I've been cooking for myself for 2 years now, and get through without a huge amount of effort. My go to ideas are as follows (I'm vegetarian, so assuming you arent, just replace tofu with meat of your choice)
Stir Fry - get onion, tofu, mushrooms, chili, carrots, capsicum, brocoli, any other vegetables you like. Cut them up and fry the shit out of them.
Curry - As above, but then add a jar of curry sauce and a tin of coconut milk/cream
Pasta Pesto sour cream vegetables if you can be bothered
Risotto - fry onion, add rice and fry that for a bit, then add water or stock a cup at a time and wait for it to absorb, then add mushrooms later. Tob with grated cheese. Not quite 30 min meal but it only requires occasional stirring/adding water so is easy anyway
Nachos - doritos can of kidney beans can of refried beans can of corn can chopped tomates an avocado sour cream jalepenos grated cheese
