Spaghetti Lasagna Florentine with Crab

Ingredients (18)

• + 1 (16 ounce) package spaghetti add to pantry
• + 2 tablespoons butter add to pantry
• + 1 (28 ounce) jar marinara sauce add to pantry
• + 2 cups fresh spinach add to pantry
• ✓ 1 cup chopped onion
• + 1 cup chopped fresh mushrooms add to pantry
• + 1 (6 ounce) can tomato paste add to pantry
• + 2 tablespoons minced fresh garlic add to pantry
• + 1 pinch cayenne pepper, or to taste add to pantry
• + 1 pinch dried parsley flakes, or to taste add to pantry
• + 1 pinch sea salt and ground black pepper to taste add to pantry
• ✓ 1 pinch sea salt and ground black pepper to taste
• + 1 pound fresh lump crabmeat add to pantry
• + 1 (15 ounce) container ricotta cheese add to pantry
• + 2 cups shredded mozzarella cheese add to pantry
• + 1 ¼ cups grated Parmesan-Romano cheese blend, divided add to pantry
• ✓ 2 large eggs
• + 2 tablespoons clam juice add to pantry