Funeral potatoes

-I seriously think these potatoes are SOOOOOOOOO good. They are my favorite.

1 pkg frozen hash browns, thawed
1 pt. sour cream
2 cans cream of potato soup
1/2 C. chopped onion
10 oz pkg grated cheddar cheese
1/2 C parmesan cheese

Mix first 5 ingredients together in 9 x 13 pan. Top with parmesan cheese. Bake uncovered for 55 minutes at 350 degrees.

(Lots of time I just add more cheddar cheese instead of buying parmesan cheese and I don't think it makes a huge difference.)