In a heavy-bottomed pot or Dutch oven, warm the olive oil and butter over medium heat until butter is melted and foaming. Add the diced onion, carrot, celery, sliced leek, and a pinch of salt. Cook, stirring occasionally, until the vegetables are softened and the onion is translucent, about 6–8 minutes.

Add garlic and herbs

Add the minced garlic, thyme sprigs, and bay leaf. Cook for 30–45 seconds until fragrant, taking care not to brown the garlic.

Seasonal vegetables

Add root vegetables and fruit

Add the diced butternut squash, sweet potato, fennel, halved Brussels sprouts, and diced apple to the pot. Stir to combine with the aromatics so the vegetables are coated with the oil and butter. Cook for 4–5 minutes, stirring occasionally, to slightly caramelize the squash and apple edges.

Liquid & seasoning

Deglaze and simmer

Pour in the apple cider to deglaze the bottom of the pot, scraping up any browned bits with a wooden spoon. Add the vegetable stock and water. Stir in the sea salt, black pepper, cinnamon, and nutmeg. Increase heat to bring the mixture to a gentle boil, then reduce to a simmer. Partially cover and simmer until all vegetables are very tender, about 20–25 minutes.

Purée & finish

Remove aromatics and blend

Remove and discard the thyme sprigs and bay leaf. Use an immersion blender to purée the soup directly in the pot until smooth and silky. Alternatively, working in batches, carefully transfer the soup to a blender and purée until smooth, then return to the pot.

Adjust texture and seasoning

If the soup is too thick, add up to 1/2 cup more water or stock to reach desired consistency. Stir in the heavy cream or coconut milk (if using) and warm through over low heat—do not boil after adding cream. Taste and adjust seasoning with more salt, pepper, or a touch more lemon juice if the soup needs brightness.

Finish & garnish

Ladle the soup into bowls. Drizzle each serving with a little extra cream if desired, sprinkle chopped parsley and toasted pumpkin seeds on top, and finish with the teaspoon of fresh lemon juice for brightness. Serve hot.