1. Prepare your dough ahead of time.
2. Fire up your Ooni Pizza Oven.
While it preheats, place your skillet pan inside with the butter and 1 tablespoon of olive oil. When it starts bubbling, add the onions and a good pinch of salt and black pepper.
3. Cook, stirring regularly, for 15 to 20 minutes, (or until the onions are soft and just beginning to caramelise at their edges).
If the onions are cooking too quickly, remove the pan and finish cooking in the residual heat. Set to one side.
4. Lightly dust your peel with flour or semolina.
Stretch the dough ball out to 12 inches on the peel.
5. Evenly scatter half the tender onions on the dough.
Repeat with half the mushrooms and asparagus.
6. Portion half the cheese then tear off and scatter fingertip-sized pieces evenly on the dough.
Garnish with the leaves of 2 to 3 plucked thyme sprigs. Drizzle with 1 tablespoon of extra-virgin olive oil and season with salt and pepper.
7. Check that the temperature on the stone is between 400 to 450˚C (752°F to 842˚F).
Slide the pizza into the oven and cook for 1 to 2 minutes or until crisp, golden, and bubbling.
8. Remove the pizza to a cutting board, and trickle over a little more olive oil.
9. Repeat for the remaining pizza and serve.
