Preheat oven to 425℉.
Peel the cipollini onions (or substitute with pearl onions or shallots if preferred), halve them, and toss in a small mixing bowl with 1 tablespoon of olive oil.
Cut mushrooms into thumb sized pieces and place in a mixing bowl Drizzle 1 Tablespoon of olive oil over mushrooms and mix well. Season with a pinch of kosher salt, a pinch of fresh rosemary and a pinch of thyme.
Place the onions and mushrooms separately on a baking sheet and roast in a 425℉ oven for 10-15 minutes. The onions may require an additional 5 minutes. Remove the mushrooms first or remove both from the oven at the same time and allow to cool before using.
Place the flatbread on a baking tray (or the back of a baking tray if transferring to a pizza stone or steel) and brush with olive oil. You can choose to flip the flatbread so the oiled side is down or keep it up.
Top with parmesan cheese, mushrooms, (shredded chicken or chopped steak if using), torn spinach, onions, mozzarella and goat cheese.
Slide flatbread onto a preheated pizza stone in the oven or bake on the baking sheet at 425℉ until crisp and golden brown. Repeat with the process with the remaining 2 flatbreads.
Remove from oven, and garnish with scallions and a drizzle of truffle oil (if using). Slice into triangles and serve.
