Hearty Beef and Vegetable Soup

500 gm Chuck Steak
2 heaped tspns Paprika
2 tblspns Vegetable Oil
8 sprigs fresh Thyme
1 chopped Onion
2 Bay Leaves
2 Carrots, chopped coarsely
2 tblspns Tomato Puree
2 cloves Garlic, chopped
300 gr chopped Potatoes
1 tbsp Cumin Seed
2 sticks sliced Celery
1.5 L Beef Stock
1 cup Sour Cr