"Posh" scrambled eggs - cook up whatever veg and meat you fancy, tip in beaten eggs, scramble, add cheese just before serving. Have with bread, toast, baguette or roll. It can be made into a non authentic shakshuka by adding a can of tomatoes before the eggs, cracking them in whole and popping a lid on. Endlessly variable - things I've added in the past (not all at once!) include bacon, ham, chorizo, tomatoes, spring onions, spinach, peppers, courgette, aubergine, mozzarella, cheddar, crème fraiche and chilli in dried, fresh and sauce form.
Fried rice is similarly quick to make and forgiving to use up any odds and ends - soy, sesame oil and sriracha add flavour, or you can head in the direction of Cajun seasoning.
If you're feeling fancy, chop veg (I like asparagus, courgette and cherry tomatoes), wrap in foil with a salmon fillet and bake. Boil mini potatoes while it cooks, then toss with the salmon juices and a squeeze of lemon.