Preheat the oven to 375 degrees F. Adjust racks to the middle of the oven. Put pizza stone in the oven to preheat while you begin the sauce.
Preheat a grill pan over medium heat.
Season the chicken with salt and pepper, to taste. Put the chicken on the grill pan and grill until cooked through. Remove to a cutting board and dice. Set aside.
Melt the butter in a medium-sized saucepan over medium heat. Add the garlic and red pepper flakes and cook until fragrant. Add the flour and cook until light blonde in color. Whisk in the cream, reduce the heat to low, and let simmer until thickened, about 2 minutes. Stir in Parmesan and season lightly with salt and pepper, to taste.
Flour your work surface and roll the pizza dough into a 13-inch diameter. Carefully remove the pizza stone from the oven and put the dough on top. Ladle the sauce to cover the bottom of the pizza. Evenly top with the baby spinach, grape tomatoes, grilled chicken and the mozzarella. Brush the edge of the crust with olive oil and season with salt and pepper, to taste. Bake the pizza until crisp and golden, about 25 minutes. Remove from oven and immediately top with another handful of spinach. Slice and serve.