Not sure what made me want to make cod and potatoes, turns out it's a fantastic tasting dish, not fishy at all for those that don't care for fishy tasting fish. I'll be making it again

1 medium carrot, shredded
1/8 cup reconstituted, dried onions (going to try fresh, diced green onions or maybe chives next time)
~6 cups mashed potatoes (I used instant)
1 cup shredded cheddar
Black pepper
Salt
4 cod loins, or enough cod fillet to cover bottom of a 9x9 baking dish
Pre-heat oven to 450. Spray cooking dish with non-stick spray, or give it a wipe with olive oil. Put cod into a single layer in the bottom of the dish. s-p-r-i-n-k-l-e carrot on top of cod, followed by the onions. Salt and pepper to taste, about 1 tbsp salt and 2 tsp pepper came out good. Layer in 3/4 cup cheese, then carefully cover the whole mess with potatoes and smooth out the top. Spreading the potatoes without messing up the cheese is hard, you're best off plopping it in by the spoonful. Add remaining cheese on top of the potatoes. Place baking dish on a jelly roll pan (it may bubble over) and cook until it begins to brown, ~25 minutes. Let stand for 5 minutes before serving.