Preheat your oven to 500F (260C) and place a pizza stone, pizza steel or inverted, level baking sheet on the center rack of the oven. I like to preheat my oven for at least 1 hour prior to making pizza. Set your pizza sauce out on the counter to come to room temperature.
Equally divide the pizza dough up depending on how many pizzas you want to make (3-6). Roll each piece of the divided dough into a tight, compact ball. Set on a lightly floured surface and lightly dust the tops with flour. Lay a clean hand towel over the top. Let rest for about 30 to 60 minutes or until the dough is no longer cool to the touch; may take longer depending on ambient temperature.
Once they are no longer cool, gently stretch the dough into pizza rounds. Cut sheets of parchment paper the size of each pizza dough round, lightly dust with flour and set the dough on top. The parchment makes it easier to get the pizzas in and out of the oven.
Cover each pizza in a light coating of pizza sauce, cover with some cheese (not too much), the mushroom and onion mixture, kale and whatever toppings make you happy (I like to add a little more cheese on top) and then bake in the center of the oven for about 10 minutes. Some ovens will take a minute or two less (a pizza oven will only take about 3 minutes), some ovens a minute or two more. You want there to be some dark charred spots on the top of the crust and the bottom should be firm and crispy (see note). Let sit for 3 minutes (this lets the cheese set a bit) and then cut and serve!