With a pizza stone situated in the bottom third, preheat the oven as high as you can get it. We use a 500°F setting on our oven.
Lightly flour your work surface. Form your pizza dough into a ball by gently stretching the top of the dough underneath itself. Place the dough on the floured work surface and pat it out gently with your hands into a disc shape until you cannot make it any wider. Flour a rolling pin and gently roll the pizza dough out. This works best if you look at the pizza dough as a clock. Start rolling from the center of the circle toward 12 o'clock, rotate your pin and roll from the center to 3 o'clock, then from the center to 6 o'clock, and so forth, ending back at 12 o'clock. Do this until you have a circle that is about 10-inches in diameter.
Sprinkle a pizza peel generously with semolina flour or cornmeal. Carefully transfer the dough to the peel. Shake gently to be sure no part of the dough sticks. This is crucial. You will be shaking the peel gently after each addition of toppings to make sure the dough can still move freely. If at any point the dough sticks, gently lift the offending area and throw a bunch of semolina or cornmeal under it.
Spread the Garlic Alfredo sauce over the dough to within a 1/2-inch of the edges. Shake the dough to make sure it's not stuck.
Sprinkle most of the grated cheese, reserving about 1/4 cup, over the Garlic Alfredo sauce. Pull off peanut-in-the-shell sized hunks of spinach and dot them over the cheese. If using the onions and anchovies, pull the onions into individual pieces and distribute them and the anchovies evenly over the top. Toss the reserved 1/4 cup of mozzarella cheese over the top. Gently shake the pizza to make sure it's not stuck.
Open your oven, position your peel over the back edge of the pizza stone. Flick your wrist to get the dough moving, pulling the peel back as you transfer the dough to the stone. Shut the oven and let the pizza bake on the stone for 8-10 minutes, or until the crust is the desired colour and the cheese is melted and bubbly with golden brown or charred areas. Slip the peel back under the pizza and give a little jerk to move it safely onto the peel. Transfer the cooked pizza onto a cutting board and let it rest 3-5 minutes before slicing.