Preheat oven to 400° F. Heat 2 tbsp of the olive oil in a large skillet and sauté sausage until golden and crispy, about 5 minutes. Place the flatbread on a large baking sheet. Brush with olive oil, top with shredded cheese, Portobello Mushroom Sauce and roasted sausage. Season with salt and pepper to taste. Place baking sheet in preheated oven and bake until cheese has melted, about 10 minutes. Before serving, remove from oven and let it warm until it is cool.