Line a 9-inch pie pan with dough. Clean and trim leeks, and julienne. Melt the butter, add leeks and season and cook covered over medium to low heat for 20 minutes until softened. Mix the eggs and cream and all but 1/4 cup of the cheese and add the cooled leeks. Pour into pie shell, top with cheese and bake for 40 minutes.
In an 8-inch skilled saute leeks in butter. Add chicken broth to almost cover. Cover pan, and to cook for about 20 minutes, until tender. Remove leeks to a platter. Reduce cooking liquid, pour over platter of leeks and garnish with fresh thyme.
Heat oil to hot, but not smoking. Toss julienned leeks with some flour in a bowl. Add to hot oil and fry. Can be used as a garnish.