Campbell's Over Rice

This was a staple for my family growing up; we called in hamburger over rice. Adaptation from Deceptively Delicious.

1 lb ground beef
1/2 c chopped onion
1 can cream of mushroom
2-4 Tb ketchup
1 Tb dry mustard
3 c cooked rice
Addition: 1 cup pureed cauliflower

Brown beef and onion. Add soup and seasonings. Heat, stirring often.
Cook rice according to package. Mix together with cauliflower.
Serve hamburger over rice mixture.