| 1 | Rinse leeks under running cold water to remove sand. |
| 2 | Cut leeks 1 inch above white base. |
| 3 | Reserve 1 green leaf for garnish; discard remaining leek greens. |
| 4 | Coarsely chop white part of leeks into pieces. |
| 5 | In medium saucepan, over medium heat, saute leeks in butter until soft, about 3 minutes. |
| 6 | Add broth and potato; cover and cook until potato is fork tender, about 20 minutes. |
| 7 | In blender container or food processor, in batches, process soup until pureed. |
| 8 | Return soup to saucepan. |
| 9 | In small dish, beat egg yolks. |
| 10 | Stir ?cup soup into yolks. |
| 11 | Slowly stir yolks back into soup. |
| 12 | Reserve 2 tb cheese for garnish. |
| 13 | Gradually stir remaining cheese into soup until melted. |
| 14 | Season with salt and pepper. |
| 15 | Pour into serving dishes. |
| 16 | Garnish each with thin strips of leek green and reserved cheese. ----- |