This is amazing. Eat it with someone you love, a lot.
3 to 4 lb leeks
2 cups coarse fresh bread crumbs (I used a kind of German whole grain bread)
3/4 teaspoon salt
3/8 teaspoon black pepper
3/4 stick (6 tablespoons) unsalted butter
1 cup heavy cream
Special equipment: large (10-12″) skillet
Preheat oven to 450°F.
Trim both ends of each leek and clean the green ends. Halve lengthwise, then cut crosswise into roughly 1 1/2″ pieces. (You should have about 8 cups.)
Cook bread crumbs with 1/4 teaspoon salt and 3/4 teaspoon pepper in 3 tablespoons butter in a pan over moderate heat, stirring, until crisp and pale golden, 3 to 4 minutes. Remove from heat.
Cook leeks with remaining 1/2 teaspoon salt and 1/4 teaspoon pepper in remaining 3 tablespoons butter in a large heavy skillet over moderately low heat, stirring occasionally, until tender, about 12 minutes.
Pour cream slowly over leeks, then scatter bread crumbs on top. Bake until cream is bubbling and slightly thickened and crumbs are golden brown, about 15 minutes.