1. Preheat oven to 350° F.
2. Arrange rack in middle of oven.
3. Butter 4 (6-ounce) ramekins and set aside.
4. Melt 1 T of butter in a large frying pan over medium heat.
5. When it foams, add onion, season well with salt and freshly ground black pepper, and cook until softened, about 1 minute.
6. Add spinach and cook until spinach is well wilted, about 2 minutes.
7. Place ham on bottom of ramekins and top with spinach.
8. Crack eggs into ramekins.
9. Place 1 T cream over each egg, and divide half of the cheese evenly among ramekins.
10. Put ramekins on a baking sheet and bake, rotating pan halfway through baking, until whites are just set but yolks are still runny, about 15 to 18 minutes.
     
11. Meanwhile, spread remaining 2 T butter on 4 slices
12. sourdough bread.
13. Top with grated cheese and toast until golden brown.
14. Serve eggs with toast.

I am not a fan of aged cheese so I just used shredded cheddar and frozen spinach.