Preheat the oven to 400 degrees F.
Place the crust on a pizza stone or baking sheet. Spread the pumpkin curry sauce all over the pizza, and top with sautéed red onion, red pepper, and spinach. Layer Havarti cheese on top. Bake for 10 minutes, until the cheese has completely melted. Sprinkle Parmesan and basil over the top before serving.