In a saucepan on medium heat melt the butter. Add the flour and cook for 1 minute while stirring.
Stir in the milk and bring the mixture to a simmer. Stir occasionally, until the mixture thickens slightly, about 3 - 5 minutes. Add the spinach and cook until the spinach has wilted about 1 to 2 minutes. Remove the pan from the heat and stir in the parmesan cheese. Season with salt and pepper, to taste. Cover with a lid on to keep warm. If the sauce is too thick, thin it out with a little more milk.
Toast the bread.
Heat the oil in a nonstick pan on low medium heat. Crack the eggs into the pan. Cook until whites are firm, about 3 - 4 minutes.
Place the prosciutto on the toast, eggs on top and spoon the spinach sauce over the eggs. Serve with sliced pear.