1. 1 stick (4 ounces) unsalted butter
2. 2 garlic cloves, smashed
3. 1 small onion, halved
4. 1 bay leaf
5. Pinch of crushed red pepper
6. One 28-ounce can diced Italian plum tomatoes, juices reserved
7. Salt
8. 2 cups spinach, stems discarded
9. 2 pounds fresh ricotta
10. 4 large eggs, lightly beaten
11. Pinch of freshly grated nutmeg
12. 1/4 cup freshly grated Parmesan cheese, plus more for serving
13. 2 cups all-purpose flour