Kielbasa Pierogi Casserole

2 (14 ounce) cans sauerkraut, drained and rinsed
1 pound kielbasa, any brand, cut into serving-size chunks
2 cans water or enough to cover meat, see note
12 frozen pierogi, any brand
1 onion, cut in rings or half rings
1/2 teaspoon caraway seeds

In a large frying pan, add all ingredients. Bring to a boil, cover and simmer until heated through. (Do not overcook or the pierogi will turn to mush.) Dish out with a slotted spoon. Serve with mustard and crusty buns or rolls.

NOTE: A can of beer can take the place of an equal quantity of water. Use just enough liquid to barely surround the kielbasa; the pierogi will steam in very little liquid.