Start by heating your oven to 400°F so it's fully hot by the time your flatbread is topped. Line a baking sheet with parchment paper to keep things from sticking. This little step also makes cleanup basically effortless afterward.
In a small bowl, stir together the olive oil, grated garlic and black pepper. This flavored oil is what makes the crust taste like more than plain bread. I like grating my garlic instead of mincing it, since it blends into the oil more smoothly.
Place your flatbread pieces on the prepared pan and brush the garlic oil generously over the top. Don't be shy here, since this is your only shot at seasoning the actual bread base before the toppings go on.
Scatter the mozzarella and gorgonzola first, then add your pear slices, walnuts and rosemary. I put prosciutto on last so it crisps up rather than getting buried under melting cheese. Spread everything evenly so each bite gets a bit of everything.
Slide the pan into the oven and bake for 8 to 10 minutes, until the cheese is fully melted and bubbling and the edges of the flatbread turn golden brown. Keep an eye on it near the end since ovens vary and it can go from perfect to overdone quickly.
Let the flatbread sit for two to three minutes before slicing so the cheese has a chance to set slightly. Drizzle with balsamic glaze if you're using it, then slice into strips and serve while it's still warm.