• 4 cups chopped leeks (about 1 large bunch) white and pale green parts only
• 4 tbsp butter, divided
• 4 large eggs
• 2 cups whipping cream
• 1/2 tsp nutmeg
• 1/2 tsp salt
• Generous grating of fresh black pepper
• 4 ounces Gruyère cheese (or cheddar)
• 1-1/2 cups bread (about 2 slices)
1. Preheat the oven to 350 degrees Fahrenheit.
2. Split the leeks lengthwise, and rinse away any grit. Then cut them crosswise into 1-inch pieces. Melt 2 tablespoons of the butter in a medium skillet or saucepan, and then add the leeks and a half-cup of water. Bring to a simmer over low heat and cook, covered, until the leeks are soft and tender and the water has evaporated. Check them frequently and stir to prevent browning, adding a little water as needed to keep them from sticking to the pan. When they’re done, after about 15 minutes, arrange in a baking dish and set aside.
3. Beat together the eggs, cream, nutmeg, salt and pepper, and pour the mixture over the leeks. Grate the cheese and sprinkle over the top. Melt the remaining 2 tablespoons of butter. Remove the crusts from the bread, tear into pieces, and grate into coarse crumbs, and then toss with the butter. (A good way to do this is to process torn pieces of bread in a food processor or blender while pouring in the melted butter.) Sprinkle the crumbs on top of the cheese.
4. Bake in the middle of the oven for an hour or until a knife inserted in the center comes out clean, and the gratin is golden brown. Serve warm.