Wash the spinach carefully and cook in a covered pan in only the water clinging to the leaves until just tender. Drain and chop or put through a food mill. Add the lemon juice.
Melt the butter and sauté the onion and garlic in it until tender. Blend in the flour. Gradually stir in the cream and bring to a boil, stirring. Season with salt and pepper to taste and the nutmeg.
Add the spinach to the sauce and mix well. Toss the noodles, spinach mixture and ham together and place in a buttered shallow casserole. Top with the crumbs. Bake for fifteen to twenty minutes, or until very hot and lightly browned.