French Leek and Ham Shepherd's Pie | Food Stuff

Ingredients

• 3 tablespoons butter
• 1 1/2 pounds cooked ham, thinly sliced
• 1 egg yolk, lightly beaten
• 1 pinch ground nutmeg
• 1/2 cup heavy cream
• 1 1/2 pounds leeks, sliced
• 2 tablespoons olive oil
• 1 onion, chopped
• 2 1/4 pounds potatoes, peeled and cut into chunks
• salt and pepper, to taste
• 1/4 cup shredded mozzarella cheese (optional)
• 2 medium tomatoes - peeled, seeded, and coarsely chopped