This deliciously Creamy Roasted Cauliflower & Potato Soup will become a fast vegetarian favorite in your menu rotation.
Cauliflower does the heavy lifting while a single potato is all it takes to create the silky texture of potato soup you love without all the carbs.
Old-fashioned potato soup is a simple, comforting favorite my mom would make when pantry supplies were few. The simplicity of a soul-food trio, potato, onion, and milk seasoned with salt and pepper still reminds me of home.
In this cauliflower soup recipe, we’ve revamped classic potato soup to tone down the carbs with cauliflower and deepen the flavor by roasting the vegetables.
Make Lower Carb Soup with Cauliflower
One potato. Yep, that’s all you’ll need for a soup that has all the creamy richness you’re craving without an excess of milk and potatoes. It is full of low-carb cauliflower and simple roasted veggies instead!
Sensitive to dairy in cream soups? It’s possible to drastically reduce or even eliminate the dairy in this recipe (see Recipe Variations below) because we borrow a super easy blender technique from our Cauliflower Alfredo.
Roasting vegetables adds layers of rich flavor to soups and sauces. Cooking the leeks, garlic, and cauliflower with a small amount of oil until edges crisp and brown creates the deeply satisfying element you won’t get otherwise.
This browning process, called the Maillard Reaction, is a simple step that reaps big rewards. It softens any sharpness in the garlic and develops an almost toasted nut flavor in the vegetables.
How to Easily Roast Garlic
- Heat oven to 400°F.
- Cut off the top third of the garlic bulb so that the majority of the cloves are exposed. (The small pieces can be saved for other recipes.)
- Place the garlic bulb in a small ovenproof dish like a ramekin or even a muffin tin, exposed cloves facing up.
- Pour olive oil over garlic bulb to coat the bulb.
- Roast 30 minutes or until garlic is soft.
- Squeeze bulb to release garlic cloves.
Add roasted garlic to soups, sauces, stews, fondue, or any savory dish to enhance flavor.
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Top 10 Tips for Roasting Vegetables to Get the Most Flavor
- Dry the vegetables after washing them so that the oil will coat them properly. The beauty of roasting is that the moisture evaporates from the vegetables and concentrates flavor. Additional water can prolong that process and cause you to lose some delicious flavor as well.
- Cut the vegetables into similar sizes for even cooking and easy eating.
- Use oil or ghee to lightly coat vegetables before roasting to help with browning.
- Turn up the heat — I find that 400°F works best. If the vegetables are already tender but not browning in a timely manner, turn on the broiler for direct high heat.
- Use the convection setting on your oven (if you have the option) as it does a better job circulating hot air around the vegetables which browns more quickly and reduces cooking time. This is why air fryers are also a great tool for efficient browning and crisping.
- Don’t crowd the pan. Spread the vegetables out on the pan so the pieces are not touching and air can easily circulate, otherwise, the vegetables tend to steam rather than roast, resulting in overcooking and less browning.
- Line shiny pans with parchment to prevent leaving the flavor stuck to the pan. If using a reliable non-stick pan, parchment may not be necessary.
- Use a sheet pan, not a baking dish. The taller sides of a baking dish protect whatever is in the dish from direct heat and you want direct heat all around the vegetables. A dark sheet pan or cast iron griddle is even better as the dark surface will speed browning. A cast iron pizza pan is my favorite for roasting vegetables because the dark finish browns them quickly and easily with its non-stick surface.
- Stir or flip the vegetables halfway through the roasting process for even browning and cooking.
- Season with salt and pepper before and after roasting. Salt is very important for elevating flavor and diminishing bitterness in vegetables. Be sure to try a bite after the roast to ensure the perfect amount of salty goodness.
Recipe Variations:
- Make it dairy-free and vegan by substituting oat milk or coconut cream for the heavy cream or simply omit the cream and puree a little more of the soup; substitute white miso for the Romano cheese to keep the umami flavor going
- Substitute sweet yellow onion for the leeks and green onion if you like a stronger onion flavor.
- Substitute celery root (celeriac) or parsnips for the potato to further reduce carbs.
- Substitute chicken broth for vegetable broth if that’s what you have on-hand.
- Customize garnishes with cheddar cheese and ham or bacon for all the loaded baked potato flavors.
- Blend it up for a delicious smooth bisque.
Cauliflower Potato Soup STEP BY STEP:
- Roast garlic bulb and cauliflower at 400°F for 30 minutes or until garlic is soft and the edges of the cauliflower begin to brown.
- Caramelize leeks and simmer potatoes in 1 cup of the stock for 10-15 minutes, or until potatoes are fork-tender.
- Stir in the cauliflower, garlic, red pepper, and Romano cheese and remaining broth; simmer 5 minutes.
- Puree 2 cups of the soup to a blender until smooth, then incorporate back into the soup.
- Stir in cream and freshly cracked pepper, continue to heat on low for 2 minutes to meld flavors.
Creamy Roasted Cauliflower & Potato Soup
An aromatic soup boasting the nutty flavors of roasted vegetables and creaminess that satisfies.
Servings: 4
Ingredients
- 1 bulb garlic (8-10 cloves), roasted; roasting oil reserved
- 4 tablespoons olive oil , or more as needed
- 1 small head cauliflower , (about 1 3/4 lb), sliced 1/4" thick
- 1 teaspoon lemon pepper
- 1 cup chopped green onions , white and light green part; scallions (green tops) reserved for garnish
- 1 cup chopped leeks (2 large), white part only, rinsed and drained
- 1 large yukon gold potato (about 1 1/2 cups) peeled and cubed
- 1/2 teaspoon sea salt
- 1/4 cup grated Romano cheese
- 3 cups vegetable stock
- 1/4 teaspoon red pepper flakes
- 2 tablespoons heavy cream , optional
- 1/2 teaspoon freshly ground pepper
Instructions
- Heat oven to 400°F. Cut top third of the garlic bulb off so that the majority of the cloves are exposed. Place the garlic in a small oven proof dish, exposed cloves facing up. Pour approximately 2 tablespoons olive oil over garlic bulb, and roast at for 30 minutes or until garlic is soft.
- Arrange sliced cauliflower on a rimmed baking sheet, brush with additional olive oil and sprinkle with a little salt and 1 teaspoon lemon pepper. Roast in the oven with the garlic for 20 to 30 minutes (stir midway through) until cauliflower is lightly browned and fork-tender. Remove cauliflower and garlic from oven and set garlic aside to cool. (NOTE: Place garlic on a separate oven rack underneath if there isn't room for both to be on the same rack.)
- While the garlic and cauliflower are roasting, cook leeks with a little olive oil over med heat until softened and beginning to brown, about 5 minutes. Add green onions, potato, 1/2 teaspoon salt, and 1 cup of the stock to the pan with the leeks; cover and simmer 10 to 15 minutes, or until potatoes are fork-tender.
- Reserve a few pices of the cauliflower for garnishing soup, if desired, and add the remaining cauliflower to the soup with the potatoes, breaking up any large pieces. Sprinkle crushed red pepper flakes over the cauliflower. Squeeze the garlic bulb from the bottom to remove garlic cloves, coarsely chop the garlic, and stir in to the soup with the Romano cheese. (Reserve roasted garlic oil for garnish, if desired.)
- Pour enough of the remaining broth over the vegetables to cover and simmer for 5 minutes, or until vegetables are all cooked through. Transfer 2 cups of the soup to a blender and puree until smooth, then incorporate back into the soup.
- Stir in cream and freshly cracked pepper, continue to heat on low for 2 minutes to meld flavors. Taste, and season with more salt and pepper, as desired. Soup can be thinned by adding more stock.
- Serve in warmed bowls and garnish with roasted cauliflower florets, scallions, and drizzle with reserved roasted garlic olive oil.
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Notes
Yields about 6 cups
Save leek dark green leaves for homemade stock.
Recipe Variations:
- Make it dairy-free and vegan by substituting oat milk or coconut cream for the heavy cream or simply omit the cream and puree a little more of the soup; substitute white miso for the Romano cheese to keep the umami flavor going
- Substitute sweet yellow onion for the leeks and green onion if you like a stronger onion flavor.
- Substitute celery root (celeriac) or parsnips for the potato to reduce carbs.
- Substitute chicken broth for vegetable broth if that’s what you have on-hand.
- Customize garnishes with cheddar cheese and ham or bacon for all the loaded baked potato flavors.
- Blend it up for a delicious smooth bisque.
Nutrition
Calories: 284kcal | Carbohydrates: 25g | Protein: 7g | Fat: 19g | Saturated Fat: 5g | Cholesterol: 17mg | Sodium: 1131mg | Potassium: 763mg | Fiber: 5g | Sugar: 6g | Vitamin A: 1169IU | Vitamin C: 87mg | Calcium: 141mg | Iron: 2mg
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Augusta says
This is the best soup I’ve ever made, wow
Judy Purcell says
Hi Augusta, I’m so glad to hear you enjoyed it so much! Thank you for taking the time to circle back and let me know, that makes my day!
Jenn Allen says
This is my kind of soup! Looks delish!
John / Kitchen Riffs says
I love roast cauliflower, and it’s terrific in soup. In fact, I have a recipe coming next week that uses it as an ingredient. This looks wonderful — and it’s cold and rainy here today, so this would be really satisfying. Thanks!