Preheat the oven to 400 degrees F.
Lightly grease a 9 by 13-inch casserole dish with 1 tablespoon melted butter. Coat the greased casserole with 3 tablespoons bread crumbs. Lay about a third of the potatoes in the casserole dish, overlapping them in a shingle pattern. Season the potato layer with 1/4 teaspoon salt and 1/4 teaspoon white pepper. Lay half the salmon slices over the potatoes and sprinkle the salmon with 1 teaspoon chopped dill. Lay half the remaining potatoes over the salmon, once again in a shingle pattern, and season with another 1/4 teaspoon salt and 1/4 teaspoon white pepper. Lay the remainder of the salmon over the potatoes, and sprinkle with 1 teaspoon chopped dill. Arrange the rest of the potatoes over the salmon and season with the remaining 1/2 teaspoon salt and 1/4 teaspoon white pepper.
Combine the eggs with the heavy cream and 2 tablespoons melted butter in a medium bowl. Whisk to combine. Pour the egg and cream mixture over the casserole and wrap with aluminum foil. Place the casserole dish in the oven and bake on the middle rack of the oven for 30 minutes. Remove the casserole from the oven, peel away the foil, and sprinkle the remaining bread crumbs over the top. Place the casserole back in the oven and bake until the top is golden brown and the potatoes are tender, about 30 minutes more.
Remove the casserole from the oven and allow to cool for 15 to 20 minutes before serving. Sprinkle the remaining 2 teaspoons of chopped dill over the casserole. Serve, drizzled with the remaining 1/2 cup melted butter and garnished with lemon wedges.
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