Take the dough out 2 hours early. Flip the dough onto the other side and spread it out in the pan. If it doesn't stretch all the way, don't force it. Cover and let it rest for an hour.
Meanwhile, start the onions. Add the oil and butter to a pan on medium heat. Add the onions and cook, stirring often, for about an hour. Slowly stir and continue to caramelize to brown and soften, adjusting the heat as needed. In the end they should be about 1/10th the volume and a deep brown color.
Check on the pizza dough and spread it out more if needed. Use your fingers to dimple the dough all over so it has a bumpy surface.
Preheat oven to 450.
Add in the sherry to the pan and stir to combine. Add in the worcestershire, thyme, and broth. Stir and bring to a simmer. Cook 5 minutes until it is a thick sauce and not watery.
Allow the onions to cool for 10 minutes. When the dough has rested about 2 hours and is nicely fluffy, top with the cooled onions. Then top with the cheese.
Bake on the floor of the oven, on a baking steel or stone if you have one.
Bake about 20 minutes until melted on top and crispy on the edges.
Remove from oven and allow to cool for 5 minutes before popping it out onto a cooling rack or a cutting board.
Cut and serve!