While crust is cooking, heat olive oil to medium high heat until shimmering. Sauté shallots until soft, about 2-3 minutes. Add mushroom slices. Let cook until seared, about 3-4 minutes, then flip, season with garlic powder, salt, and pepper, and sear an additional 3 minutes. Remove from heat.
Top pizza with a layer of Pumpkin Marinara, the mushroom and shallot mixture, and cheese. Put back in oven until golden and cheese is bubbly. Remove from oven, let stand for 5 minutes, then serve.