Toss the pumpkin pieces with 1 tablespoon of olive oil, salt, pepper, and thyme.
Spread the pumpkin out on a baking sheet and roast for about 25-30 minutes, or until the pumpkin is tender and lightly browned.
Break up sausage and spread out on a rimmed baking sheet. Bake until sausage is lightly browned and cooked through, about 10 minutes.
Increase the oven temperature to 475 F, or prepare a pizza oven.
Stretch or roll out the dough on a floured surface to your desired thickness.
In a small bowl, combine the ricotta cheese and minced garlic. Mix well.
Brush the pizza dough all over with the remaining 1 tablespoon olive oil.
Scatter the mozzarella evenly over the pizza dough.
Dot the ricotta-garlic mixture over the top of the mozzarella.
Spread the roasted pumpkin pieces evenly over the ricotta layer.
Sprinkle the cooked sausage over the pumpkin.
Place the pizza in the preheated oven and bake for about 12-15 minutes, or until the crust is golden brown and the cheese is bubbly and lightly browned.
Remove the pizza from the oven and let it cool for a few minutes. Sprinkle with sage leaves. Slice and serve hot.