As the chef-owner of Denver's new Acorn restaurant, as well as OAK at Fourteenth in Boulder, Colorado, Steven Redzikowski contends with some cold days. "Soup should always be one of, if not the, most seasonal things on the menu," he says. "And it's certainly something we turn to as soon as autumn hits and we want more warmth from our meals."
Seasonal in autumn, of course, means winter squash and root vegetables, and so this season Redzikowski was quick to put his roasted pumpkin soup on his OAK menu. "People go bananas for it," he says. "And we'll use it at Acorn, but most likely as a sauce, because Acorn is more of a shared-plate restaurant, and in my opinion, soup isn't the most terribly natural thing to share."
What makes people crazy for Redzikowski's pumpkin soup is its blend of savory and sweet. "When people cook a butternut squash soup or sweet potatoes, they'll often use a little brown sugar," he says. "We like to use our homemade marshmallow with pumpkin." The soup stock (parsnip-based), which he makes after wood-firing herbs and roasted vegetables as well as pumpkin, is super smooth. "We blend the heck out of it," he says. "Then we pour it, table-side, over a heated bowl that already contains smoky, blowtorched pieces of spiced marshmallow. When the soup hits the marshmallow, the sticky candy melts, and it creates a really nice sweet note without overpowering the nutty, earthiness of the pumpkin."
Redzikowski's tip for finding pumpkins is easy: They should be in most seasonal grocery stores come fall (yes, you can buy your marshmallows in a bag). And don't worry about organic squash – you just want to find a pumpkin that hasn't been sitting on its side for a while and/or looks a little flat or brown on one side. "It's pretty easy to roast pumpkin," Redzikowski says. "I won't say you can't overcook them, but it's hard, and to find out if it's done, I just stick a pairing knife into its thickest portion and make sure I can remove [the knife] without resistance. You want the flesh, like many a comforting cold-weather dish, to be super tender."
Roasted Pumpkin Soup
• 2 pumpkins, cut in half, seeds removed, and peeled
• 1 parsnip, peeled and sliced thin
• 1 1/2 carrots, peeled and sliced thin
• 1 1/2 head celery root, peeled and sliced thin
• 1/4 head celery, sliced thin
• 1/4 pint olive oil
Place all vegetables into a roasting pan and drizzle with olive oil, salt and pepper, and roast in a 350° F oven until vegetables are tender. While roasting, continue to stir the veggies every 15 minutes, being careful not to char them.
Once vegetables are tender, place in a large stockpot and cover with parsnip stock (recipe below). Simmer for 20 minutes.
Transfer to a blender, and blend until very smooth. Adjust flavor with salt.
• 6 parsnips
• 1 gallons water
Simmer until the parsnips are tender.
Strain the liquid through a fine strainer and reserve.
Marshmallows (in grams because the measurements have to be exact)
• 390 grams sugar
• 15 grams corn syrup
• 335 grams water
• 12 sheets gelatin
• 14 grams vanilla extract
• 65 grams egg whites
• 70 grams confectionery sugar
• 70 grams corn starch
• 5 grams ground cinnamon
• 2 grams ground allspice
• 2 grams ground nutmeg
• 525 grams sage, chopped fine
In a medium saucepan, combine granulated sugar, cornstarch, three-quarters of the water, and cook to 260° on a candy thermometer.
Bloom (soften) gelatin in a bowl of cold water, and reserve.
In another saucepan, combine spices, chopped sage, vanilla, and bloomed gelatin. Allow to steep over low heat.
While sugar syrup is heating, place egg whites in a Hobart or KitchenAid stand mixer. With the whisk attachment, whisk until whites have doubled in size. Drizzle in the spice mix and fold in the gelatin sheets.
While mixer is running, drizzle the hot syrup into the spice-gelatin-egg whites mixture, and whisk for 7 to 10 minutes until fluffy but not set. Quickly pour into a greased terrine mold or a Tupperware container that has been dusted with cornstarch so the marshmallow will release easily when set.
Once the marshmallow has set, remove from the mold or the container, and cut into 2 inch-by-2 inch squares. Reserve the squares.
Using a blowtorch or fire, char (as for crème brûlée) the outside of 4 marshmallow squares. Reserve.
Pour 8 oz of the hot soup into each of four soup bowls, and garnish each with one brûléed marshmallow and a fried sage leaf. Alternatively, put one brûléed marshmallow in each bowl and pour in 8 oz of soup per bowl; garnish with a fried safe leaf.