Place a pizza stone in the oven and preheat it to 425 degrees.

Add the sausage to a skillet and cook over medium heat for 5-7 minutes. About halfway through, add the mushrooms. Saute until mushrooms are browned and sausage is cooked through. Remove from heat and set aside.

Place the naan breads on a piece of parchment paper on top of a flat cutting board or cookie sheet (this makes the transfer to the pizza stone much easier!). Spread a heaping Tablespoon of pesto over each piece. Divide the mozzarella and gouda cheese evenly between them. Spread the sausage and mushrooms over the pizzas then finish with a sprinkling of Parmesan cheese.

Slide the parchment paper onto the hot pizza stone. Bake for 10-12 minutes or until cheese is melted and just starting to brown around the edges.

Top the pizzas with the arugula leaves and chopped green onions. Serve immediately.