A delicious twist on a classic Potato Leek Soup, with the addition of parsnips and a bright chive gremolata. This easy vegan soup cooks itself in the oven. You won't need to dirty a single pot!
Preheat: Preheat oven to 400°F. Line a large baking sheet with parchment paper (see note 3).
Prep garlic for Soup: Slice top off the head of garlic. Place garlic on foil and drizzle 2 teaspoons of the olive oil over the cut side. Wrap tightly with foil and place on baking sheet.
Roast vegetables: Add potatoes, parsnips, leek, and onion to baking sheet. Drizzle with the remaining 2 tablespoons of olive oil. Toss to coat. Sprinkle with ¼ teaspoon of the salt. Bake until fork tender and golden brown on the edges, about 40 minutes, flipping vegetables halfway through.
Make Chive Gremolata: Meanwhile, in a small bowl, stir together chives, parsley, lemon zest, salt, and red pepper flakes (to taste). Cover and refrigerate until needed.
Blend soup: Transfer roasted vegetables to a blender. Unwrap and squeeze head of garlic over blender, to release the soft garlic cloves (discard garlic peel). Add vegetable stock, lemon juice, white pepper, and remaining ¼ teaspoon salt. Blend until smooth, thin with more broth if needed. Taste and season with more salt, if needed.
Heat soup: If you have a high-speed blender, heat soup directly in blender (see note 4). Otherwise, transfer to a pot over medium heat. Pour hot soup into bowls, garnish with chive gremolata.
Notes
Potatoes: You can peel the potatoes if you'd like - or leave them unpeeled. Peeled potatoes will make a lighter colored soup (like the one photographed). The russet potatoes could be substituted with Yukon Gold (or similar) instead.
Lemon juice & zest: In this recipe, the zest will get used later for the Chive Gremolata. Zest the lemon first and set the zest aside (for later), then squeeze it for the juice.
Large baking sheet: When roasting vegetables, use the biggest baking sheet you have. Spacing out the vegetables encourages them to roast, rather than steam. A "half sheet" (18 x 13-inches) should provide enough space for this recipe. But if your baking sheets are smaller, you may need to divide the vegetables across two baking sheets. If using two baking sheets, position the racks in the upper and lower-thirds of the oven, and rotate the sheets halfway through.
High speed blenders: High speed blenders, like Vitamix, usually heat food from the friction of the blades. Follow manufacturer's directions (e.g. for Vitamix, blend on high speed for about 6 minutes, or until hot). Some high speed blenders have a "soup" setting directly built in.