2 pounds parsnips, peeled and cut into 1/2 inch pieces
3 carrots, peeled and cut into 1/2-inch pieces
2 tablespoons olive oil, divided
sea salt and ground black pepper to taste
1 large onion, diced
3 stalks celery, diced
1 tablespoon butter
1 tablespoon brown sugar
3 cloves garlic, minced
1 teaspoon ground ginger
½ teaspoon ground cardamom
½ teaspoon ground allspice
½ teaspoon ground nutmeg
¼ teaspoon cayenne pepper
4 cups chicken stock
1 cup whole milk
½ cup heavy cream
Preheat the oven to 425 degrees F (220 degrees C).
Place parsnips and carrots in a mixing bowl; sprinkle with 1 tablespoon olive oil and toss to coat. Season with salt and pepper. Spread vegetables evenly onto a baking sheet.
Roast in the preheated oven until vegetables are tender and parsnips are golden brown, about 30 minutes.
Heat remaining 1 tablespoon olive oil in a large saucepan over medium heat. Cook and stir onion and celery in hot oil until softened and onion is beginning to turn golden brown, about 5 minutes. Reduce heat to low; stir in butter, brown sugar, garlic, and roasted parsnips and carrots. Continue to cook and stir until vegetables are very soft and beginning to brown, about 5 to 10 minutes.
Season with ginger, cardamom, allspice, nutmeg, and cayenne pepper; stir for 1 minute. Pour in chicken stock; bring to a boil over medium-high heat. Reduce heat to medium-low, partially cover, and simmer gently for 5 to 10 minutes.
Working in batches, pour soup into a blender, filling the pitcher no more than halfway full. Hold down the lid of the blender with a folded kitchen towel and carefully start the blender, using a few quick pulses to get soup moving before leaving it on to purée. Pour blended soup into a clean pot.
Stir in milk and cream. Return to a simmer over medium-low heat. Season with salt and pepper to serve.
