Place a pizza steel or stone on the middle rack and preheat the oven to 425 degrees F.
Slice the delicata in half lengthwise and scoop out the seeds. Slice into ¼-inch half moons.
Toss the squash with olive oil, salt and pepper and spread on a rimmed baking sheet. Roast for 10 minutes, just until the squash starts to soften.
Increase the oven to 550 degrees F and let the steel or stone heat for at least 30 minutes.
While the oven heats, whisk together the ricotta, parmesan, olive oil, garlic powder, salt and pepper. In a separate small bowl, toss the sage leaves with 2 teaspoons olive oil.
Stretch one dough ball into a round and brush with olive oil. Spread half the ricotta sauce over the top, leaving a border for the crust.
Sprinkle with a scant ¾ to 1 cup mozzarella. Top with half the squash, red onion and sage leaves.
Bake for about 10 minutes, until the cheese is bubbly and the crust is crisp at the edges with a good chew. Note that bake time is dependent on what pizza stone or pan you use and the thickness of the dough.
Finish with grated parmesan, a drizzle of olive oil and cracked pepper or red pepper flakes.
Let the steel or stone reheat for a few minutes, then repeat with the second dough ball.