Preheat oven to 220 degrees C. Butter a shallow baking dish.
Beat together the melted butter, eggs, half the sugar, lemon zest and nutmeg. Stir in the sliced apples.
Cook the lasagne sheets in a large saucepan of boiling water until al dente, about 6 minutes. Drain. Layer the lasagne with the apple mixture as though making a lasagne. Sprinkle the top with the remaining sugar. Bake until golden, about 30 minutes.