Make the caramelized onions:

1. Slice the onions lengthwise from root to stem so they will hold their structure once caramelized. Heat the oil and butter in a large skillet on medium-high heat. Add the onion and stir to coat before spreading evenly in the pan. Reduce the heat to medium and allow the onions to cook without stirring them for 10 minutes.
2. Stir the onions and continue to cook on medium or medium-low for 30 more minutes, stirring every 5 minutes or so. If they look dry, you can add a tablespoon of water.
3. In the last 15 minutes of the cooking time, you will need to stir the onions more often so they don’t stick to the pan and burn.
4. Remove from the heat and set aside. They can be stored in a covered container in the fridge for one week or frozen for 3 months.

Roast the pepitas:

1. Stir together the pepitas, paprika, cumin, salt, and oil. Pour the seeds onto a parchment-lined rimmed baking sheet and spread out into an even layer. Roast at 350 F/176C for 12 minutes, stirring once.
2. Remove from the oven and let cool. Once cool, they can be stored in a covered container on the countertop for several weeks.

Make the soup:

1. Sauté the onions in a large pot until they are just tender.
2. Add the pumpkin, garlic, broth, celery seed, salt, and pepper. Bring the mixture to a boil, then lower the heat and simmer for 20 minutes.
3. Remove the pot from the heat. Use an immersion blender to puree the soup until nearly smooth.
4. Ladle the soup into serving bowls. Top with a spoon of caramelized onions, roasted pepitas, and chopped parsley.