Spread 1 tablespoon Boursin cheese onto each flatbread.
Top with 1/4 cup mozzarella on each.
Layer 1/2 cup of mushrooms onto each flatread and place in the oven and bake for 7-10 minutes until the cheese has melted and the flatbread is golden brown.
Take out of the oven and top with 1/4 cup of arugula for each flatbread. Serve immediately.