Let's start with the sauce. In a small pot placed over medium heat add in the garlic and butter. Allow to melt and bubble. Once melted add in the flour and stir. Allow the flour to "cook out" for about 1 minute. Next pour in the milk and stir until smooth. Continue to stir and you will notice sauce begins to thicken very quickly. Add in parm, salt, garlic powder. The long you cook the thicker it will get. Add in a tbs of milk to thin out sauce if needed. Set sauce to the side.
Preheat the charcoal grill or the oven to 500F. I like to place a pizza stone in the oven to get hot as this results in a crispy bottom pizza.
Grab your pizza dough and form to 12 inch pizzas. Top with béchamel sauce, chopped broccoli, and chopped mushrooms. Add on cheese, and boursin. I like to build my pizzas on parchment lined cutting board paper topped with a bit of cornmeal. This allows you to build the pizza and then easily slide it onto the pizza stone when the time comes.
Once bbq or oven is at temp, slide the pizza onto the pizza stone allow the pizza to bake for 10-15 minutes.
Once pizza is done cooking, remove from heat and top with fresh lemon zest, arugula, parm, and olive oil. Enjoy!