For the sauce: In a small saucepan over medium heat, add 2 tbsp butter. Once butter is melted, add flour, basil, garlic, salt and pepper. Stirring frequently, slowly add milk. Once sauce thickens, about 3 minutes, remove from heat and set aside.
Preheat oven to 475 degrees. Place pizza stone in the oven for 20-30 minutes to get stone nice and hot. - skip this step if you are using a pizza pan.
On a piece of parchment paper, stretch pizza into about a 12" circle using your hands or a rolling pin. Then gently fold all edges of the pizza over to form crust. About a 1/2" all the way around the edges.
Evenly spread white pizza sauce over pizza. Then, evenly sprinkle spinach, mushrooms and bacon on top of the sauce. Next drop tablespoons of ricotta cheese evenly on top of the pizza. Finally, sprinkle with mozzarella cheese.
Carefully transfer pizza with parchment paper to the hot stone or baking sheet.
Bake in the oven at 475 degrees for 10 minutes. Bottom will be golden and top will be lightly bubbly.
Carefully remove pizza from the oven and let cool. Slice and serve immediately!