Preheat oven to 400º F. Roast the butternut seasoned with a pinch of kosher salt, black pepper, and thyme, until the butternut begins to brown on the edges, about 15 minutes. Remove from oven and let cool. 

On a sheet of parchment paper, Stretch the dough out to about 12” on the long side. 

Season the ricotta with kosher salt and pepper and set aside. 

Sprinkle the mozzarella and pecorino over the dough. Dollop the ricotta over the grated cheese. Scatter the roasted butternut squash evenly over the cheese. Top with torn pieces of prosciutto. Bake the flatbread for about 15-20 minutes, until the crust has risen, is golden brown, and the cheese is melted.