Preheat the oven to 400°F (200°C). Brush both sides of the bread slices lightly with olive oil and toast in a skillet over medium heat until golden brown, about 2–3 minutes per side. Set aside.

In the same skillet, melt butter with a bit more oil over medium heat. Add shallot and cook 2–3 minutes until soft. Stir in garlic 30 seconds, then add cherry tomatoes (or crushed tomatoes), thyme, red pepper flakes, and a pinch of salt. Simmer 6–8 minutes until slightly reduced and glossy. Stir in cream and simmer 1–2 minutes until silky.

Push the sauce to one side of the skillet and add spinach with a splash of olive oil and a pinch of salt. Toss 1–2 minutes until just wilted, then briefly combine with the sauce.

Lower oven temperature if using an ovenproof skillet. Place toasted bread slices in the pan or a shallow baking dish. Spoon a generous layer of spinach and sauce over each slice, leaving a small well in the center for the egg.

Carefully crack one egg into the well on each bread slice. Sprinkle grated cheese evenly over and around the eggs. Optionally tuck a slice of prosciutto beneath each egg.

Transfer the skillet or dish to the oven and bake 10–14 minutes depending on yolk preference: about 10–11 minutes for runny yolks, 12–14 minutes for jammy yolks. Watch for opaque, set whites and slightly jiggly yolks.

Remove from oven, let rest 1–2 minutes. Spoon any remaining warm sauce over the tops, scatter fresh basil or parsley, and drizzle extra olive oil. Serve warm.