Ripieno di Spinaci, Ricotta e Prosciutto

• 2 pounds fresh spinach, or 2 packages (10 ounces each) frozen chopped spinach,

If using fresh spinach, rinse it well, then place it in a saucepan with the rinsing water clinging to the leaves and cook until wilted, 3 to 5 minutes. Drain well, squeeze out excess moisture, and chop finely. If using thawed frozen spinach, squeeze dry.

Melt the butter in a large sauté pan over medium heat and let it color just slightly. Add the spinach and toss it in the butter for a