Step 1: Prepare the Dough

1. Preheat the Oven: Preheat your oven to 475°F (245°C). If you have a pizza stone, place it in the oven to heat up as well; otherwise, use a baking sheet.
2. Roll Out the Dough: On a lightly floured surface, roll out the pizza dough into a 12- to 14-inch circle. Transfer the dough to a pizza peel or baking sheet dusted with cornmeal or flour to prevent sticking.
3. Brush with Olive Oil: Brush a thin layer of olive oil over the dough to promote a crispy crust when baked.

Step 2: Make the Pumpkin Sauce

1. Combine Ingredients: In a small bowl, mix the pumpkin puree, minced garlic, ground sage, nutmeg, salt, pepper, and olive oil. Adjust seasoning to taste.
2. Spread on Dough: Spread a thin, even layer of the pumpkin sauce over the pizza dough, leaving a small border for the crust.

Step 3: Caramelize the Onions

1. Heat Butter in Skillet: In a medium skillet, melt the butter over medium-low heat.
2. Cook Onions Slowly: Add the sliced onions and cook, stirring occasionally, for 10-15 minutes until they turn golden brown and caramelized. If desired, add 1/2 teaspoon of sugar for extra sweetness. Once done, remove from heat and set aside.

Step 4: Add the Toppings

1. Add Cheese and Onions: Sprinkle the Havarti cheese evenly over the pumpkin sauce, then layer the caramelized onions on top.
2. Add Fresh Herbs: Sprinkle fresh thyme or rosemary leaves over the pizza for an aromatic finish.

Step 5: Bake the Pizza

1. Bake: Slide the pizza onto the preheated stone or place the baking sheet in the oven. Bake for 10-12 minutes, or until the crust is golden and the cheese is melted and bubbly.
2. Broil (Optional): For a bubbly, browned top, broil the pizza for 1-2 minutes at the end. Watch closely to prevent burning.

Step 6: Garnish and Serve

1. Add Fresh Arugula and Balsamic Glaze: Once the pizza is out of the oven, top it with fresh arugula leaves and drizzle with balsamic glaze for a touch of sweetness and acidity.
2. Serve: Slice and enjoy the warm, savory flavors of pumpkin, Havarti, and caramelized onions in every bite.