Preheat the oven to 400°F.
Roll out the puff pastry on a lightly floured surface to fit a 9-inch tart pan. Place the pastry in the pan and trim any excess.
Layer the prosciutto evenly over the pastry, followed by the chopped spinach and shredded mozzarella cheese.
Create four small wells in the cheese layer and crack an egg into each well. Drizzle olive oil over the eggs and season with salt and pepper.
Bake in the preheated oven for 20-25 minutes, or until the pastry is golden brown and the eggs are set to your liking.
Remove from the oven and let cool for a few minutes. Garnish with fresh herbs before slicing and serving.