Hash - start this early. If using Idaho potatoes ie russet, dice them and then rinse them well to remove starch, otherwise you will end up with a gummy mess. Red potatoes, golden potatoes, and yams have less starch so they aren't a problem. Throw them in a non-stick skillet with some diced onion and get it cooking. Add a little oil, butter, or better yet some diced bacon. If you have left over meat from dinner, dice it up small and throw it in; chicken breast not that great because it dries out. Sausage of any type works great. Fresh herbs work. Left over peppers can be diced and tossed in as well as mushrooms. Sprinkle a little Worcestershire sauce to add umami and you are set. Just let it cook. A non-stick really helps to keep the tasty browed bits on the food and not on the pan.

Here is a simple Sweet potato (yam) hash with onion and a bit of sriracha.

Mushrooms - Wild are best but any will work. They don't have to cook a long time like hash. Std mushroom approach a little fat (oil, diced bacon, butter), Worcestershire sauce, garlic, salt, pepper. I you have it, some diced shallot, onion or scallion are nice.

Here is linguica(Portuguese sausage) and wild mushrooms

Here it is served with pan toasted ciabatta and shaved Parmesan

Here are eggs with mushrooms and ramps