Crescent Roll Casserole

1 ½ lb very lean ground beef
1 medium onion, chopped
1 lb crushed tomatoes, fresh or canned
1 ½ tsp salt plus more as needed
Freshly ground black pepper
2 C (apx 6oz) shredded sharp cheddar cheese
2 C (apx 6 oz) shredded mozzarella cheese
4 Pillsbury refrigerated Crescent dinner rolls (unbaked)
¼ C sour cream

Preheat oven to 375°.

In a large flame-proof baking casserole, brown the beef with the onion over medium heat, stirring to break up the meat, until the beef turns color, about 12 minutes. Add the tomatoes and stir. Season with 1 ½ tsp. of salt and some pepper. Cook, stirring occasionally, until the liquid evaporates, about 20 minutes. Remove the casserole from the heat.

Mix together the cheddar and mozzarella cheeses and sprinkle over the meat in the casserole. Unroll the crescent rolls and spread one side of each roll with 1 tbsp of sour cream. Cover the cheese with the rolls and the sour creamed side up. Bake the casserole until bubbly and the top of the crescent rolls are golden brown, about 35 minutes.