Preheat oven to 500°F with baking steel on the top rack of the oven for at least 1 hour before use. Remove pizza dough from fridge to come to room temp on the counter.
Prep your toppings: grate the mozzarella cheese, slice the onion, and shred the pork.
Turn on your oven's broiler function if it has one.
Stretch the pizza dough into a 12-14" round and transfer to a pizza peel dusted with a 50/50 blend of semolina flour and all purpose flour.
Spread the BBQ sauce across the surface of the dough with the back of a spoon, taking care not to tear the dough.
Then, sprinkle on an even layer of the shredded mozzarella cheese, bringing the cheese all the way to the edges of the sauce.
A layer of pulled pork goes down next, followed by the red onions. Use a microplane to grate a fine layer of parmesan cheese over the top.
Give the pizza a shake on the peel to make sure it hasn't stuck. Then, slide it onto the baking steel: Pull the top oven rack out and place the tip of the peel near the back of the baking steel at a low angle. Quickly pull the peel backwards out of the oven, letting the pizza slide off and onto the peel.
Cook the pizza for 2 minutes with the broiler on, then turn the broiler off, rotate the pizza, and cook for an additional 2-3 minutes until crispy and lightly blackened on top.
Use the peel to remove the pizza from the oven, slice into wedges, and serve immediately.