| 1 | Melt half the butter in heavy large deep skillet over medium heat. |
| 2 | Add onions and bell pepper and saut?until light golden, about 10 minutes. |
| 3 | Add mushrooms and saut?until starting to soften, about 5 minutes. |
| 4 | Mix in flour and paprika and stir 2 minutes. |
| 5 | Mix in stock and tomato paste. |
| 6 | Bring to boil, stirring constantly. |
| 7 | Boil until sauce thickens and paprika flavor mellows, stirring frequently, about 8 minutes. |
| 8 | Mix in sour cream. |
| 9 | Remove from heat and add dill. |
| 10 | Season to taste with salt and pepper. |
| 11 | (can be prepared 1 day ahead. |
| 12 | Cover and refrigerate. |
| 13 | Bring to simmer before adding beef). |
| 14 | Melt half of remaining butter in another heavy large skillet over medium-high heat. |
| 15 | Working in batches, add beef, season with salt and pepper and cook until just brown on each side. |
| 16 | Transfer to plate. |
| 17 | Add more butter as needed. |
| 18 | When all beef is brown, add to sauce along with any drippings on plate. |
| 19 | Add dry white wine to skillet and bring to boil, scraping up any browned bits. |
| 20 | Boil until syrupy, about 3 minutes. |
| 21 | Add to beef. |
| 22 | Sprinkle with chopped tomatoes before serving, if desired. |
