Put pork in a medium roaster; add onions and garlic. Braise slowly for 1 hour. Add water, mushrooms, paprika, parsley, salt and pepper.
Lower oven temperture to 350 degrees. Cook pork in roaster, uncovered, for 1 and 1/2 hours longer.
Make a roux with oil and flour - warm oil in small skillet, stir in flour until smooth and brown. Put the roaster on a burner, bring to a boil, and stir in the roux; let thicken slightly. Stir in the sour cream. Best served with wide egg noodles!