This Roasted Cauliflower Soup Recipe has a complexity that convinces you there must be some lavish secret ingredients. But, that’s anything but the truth. Roasting cauliflower, produces a depth of flavor that evokes winter truffles. This, when combined with it’s velvety texture, makes for pure culinary magic.
Besides being delicious as a soup, this recipe can also be a versatile sauce. I have used this cauliflower soup recipe with fish, poultry, and wild game dishes. Since it’s flavor profile is delicate and smooth, as a sauce it really allows the subtle nuances of the entrée to be the focal point. This soup, can also be used as a healthy swap for cream in mashed potatoes and pasta sauces.
Helpful tips for making this Roasted Cauliflower Soup Recipe
Roasting the Cauliflower
- Cut all of your cauliflower relatively the same size. this will ensure that it all cooks evenly. I suggest erroring on smaller rather than larger pieces. With more surface area, you enable more of the cauliflower to brown while roasting, this contributes to the flavor of this roasted cauliflower soup recipe.
- Brown but don’t burn. Roasted cauliflower has this amazing nutty caramelized taste when it browns in the oven. By roasting at 375 F / 190 C, the cauliflower gradually develops flavor as it darkens with less risk of burning. But, any florets that go too far and turn black should be picked through and discarded. As this is a pureed dish, the burnt pieces will ooze a bitterness that will ruin your cauliflower soup.
- Do not crowd your roasting pan. If your cauliflower is not give space, it will steam versus caramelizing in the oven. Avoid having it packed so tight you can not see the pan below.
- Rotate and stir after twenty minutes. Only after your cauliflower has started to develop some color, you should rotate and stir it. This will give all of it’s sides a chance to brown. Also, redistribute cauliflower from the sides and center of your pan to assist even cooking. If any florets seem stuck, use a wooden spoon or spatula to scrape them free.
- Reserve some roasted cauliflower for garnish. Prior to transferring the cauliflower from the roasting pan to the pot, pick through and save about a cup for garnish. Having some to show show the main ingredient for the soup is a good marker and will add just a few bites of texture to the bowl.
Sweating The Aromatics
- Low and Slow. When sweating the onions and celery, place your pot over a medium to low heat and allow them time to gradually soften. Five minutes at the minimum, fifteen is even better before adding the cauliflower and water. I suggest starting them halfway through roasting the cauliflower. Since we are not adding any herbs or spices to this roasted cauliflower soup recipe, we want to develop depth of flavor with of each ingredient through technique. They will take on a sweeter flavor the longer they are allowed to sweat.
- Do not brown your aromatics. Unlike the roasted cauliflower, we want to avoid any color in the aromatics. Their flavor needs to remain subtle and sweet. I find starting my pot on a medium heat and then reducing it to low after the first few minutes helps avoid any browning.
Blending The Cauliflower Soup
Reserve Some of the liquid before blending. One of the most important steps is making sure you have the correct ratio of liquid to solids. So before you start blending, reserve at least one cup of the liquid. This way you can adjust for consistency. If you skip this step and your roasted cauliflower soup ends up too thin, you will have to return it to the stove to reduce. This can be problematic as a blended soups can stick and scorch when kept over heat.
Blend on high for minutes not moments. This recipe in particular benefits from some additional time in the blender. In cooking, we usually want to avoid overworking things, as it commonly leads to less desirable textures. But in the case of cauliflower soup, we want to break down all the fibrous stands to improve texture.
Pass it through a Chinois. Regardless of how high power of a blender you use, passing your soup through a chinois will improve it’s texture. Chinois are a very fine mesh strainer that are used in professional kitchens to strain soups and sauces. By using the bottom of a ladle to help force the soup through the strainer you can make quick work of this task. To cut down on dishes, I will typically wipe my pot of any remaining sediment while blending.
To check the consistency, dip a spoon into the blended soup. The soup should lightly coat the spoon. If you can run a finger through it and the borders of the trail hold, you have achieved the right texture.
Equipment Needed to Make this Recipe
In order to make this Roasted Cauliflower Soup Recipe you will need the following tools. These are items I personally use and recommend. Any purchases made through the Amazon Affiliate links earn a small commission that support this website.
- A Heavy Bottomed Pot, at least 5 quarts in size.
- Measuring Cups
- Measuring Spoons
- High Power Blender
- Chinois, a Fine Mesh Strainer.
- Wooden Spoon
- Chefs Knife
- Cutting Board
- Vegetable Peeler
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Roasted Cauliflower Soup Recipe
- 1 Tsp Green Herb Oil
Roasting the Cauliflower
- Preheat Oven to 375° F/ 190° C. Then divide your cauliflower at the stem. Separate florets into even sized pieces. Dice the stem roughly the same size.
- Lightly toss cauliflower in olive oil and kosher salt. Spread evenly in a roasting pan, making sure to leave some space between the florets. Place in oven and set timer for 20 minutes. Note: Total roasting time will be between 30-40 minutes.
- After 20 minutes, check on cauliflower. Once some browning has started to develop use a spatula to gently stir and redistribute within the roasting pan. Place back in the oven for an additional 10-15 minutes to continue browning. Be careful to not burn your cauliflower.
- Remove cauliflower from oven. Allow it to cool briefly. Pick through and reserve some of the best looking florets for garnish. Also trim or discard any florets that have burned.
Cooking Roasted Cauliflower Soup
- While the cauliflower is roasting in the oven. Small dice the onion and celery.
- Place a heavy bottomed pot that holds at least 5 quarts of liquid over medium heat.
- Place olive oil, onion, celery, black pepper, and half the recipe's salt in the pot. Cook over medium to low heat, sweat till the onions are translucent, about 10-15 minutes. Stir occasionally.
- Once onions are translucent, add water and simmer over low heat till cauliflower has finished roasting.
- Add cauliflower and grated parmesan cheese. Cook for an additional 5-10 minutes before blending.
Blending Roasted Cauliflower Soup
- Remove soup from heat and reserve one cup of liquid. Transfer the remaining soup to a blender with heavy cream.1 Cup Heavy Cream
- Starting on low and gradually increasing speed to high, puree cauliflower soup for 3-5 minutes or until it is completely smooth.
- Check consistency, if soup is too thick add back some of the reserved liquid. Taste for seasoning and add additional salt or pepper if necessary.
- Blend for an additional minute if any adjustments were necessary. Meanwhile clean your cooking pot of any sediment.
- Place a Chinois, or fine mesh strainer in your cooking pot. Pour the cauliflower soup into the Chinois. Use a ladle to work the soup through the strainer.
- Taste for seasoning again and make any adjustments.
- Serve immediately using the reserved cauliflower florets as garnish. Or place your soup into an ice bath to cool. Store refrigerated up to 5 days.
Choosing Ingredients for this Roasted Cauliflower Soup Recipe
This roasted cauliflower soup recipe was based upon using one large head of cauliflower. This is going to be your most cost effective method of making this soup. In some supermarkets you can purchase already separated and washed cauliflower florets, that would be a good option as well.
Avoid using frozen cauliflower for this roasted cauliflower soup recipe. Frozen cauliflower will not roast the same way fresh. Basically, it does not caramelize the same way or retain it’s internal moisture. This will negatively effect the flavor of your soup.
There is a small amount of grated parmesan cheese in this recipe. It is used to add some umami flavors and additional seasoning. For your best results use a wedge of quality parmesan cheese and grate it yourself. Otherwise most grocery stores offer a grated parmesan that is refrigerated. This is also a good option. Avoid using a powdered, shelf stable parmesan cheese.
The addition of cream to this roasted cauliflower soup recipe adds to the luxurious texture. I suggest using a heavy whipping cream as it will contribute the most in terms of richness. Using half and half would work if you needed to make a substitution or if you wanted to reduce the fat content.
If you wanted to make this recipe vegan, you could certainly use a dairy alternative. I prefer nut based dairy alternatives for this recipe. Additionally, I would suggest adding some mushrooms for added body and umami in that scenario.
Use a yellow, sweet, or Vidalia onion for this recipe. The use of a red onion may tint your soup slightly purple.
Common Questions Asked about Cauliflower Soup
Do I need to pass my Soup through a Chinois?
You do not necessarily need to pass your soup through a chinois. But doing so will improve the overall texture. If you do not own a chinois, using a fine mesh strainer will still aid in straining out any larger sediment. Otherwise, make sure that you blend your soup for additional time. Since this roasted cauliflower soup recipe does not have any ingredients that would start to become gummy or develop gluten, it is safe to spend some extra time in the blender. But, that isn’t true for all pureed soups.
Can I use White Pepper instead of Black Pepper?
Yes, but use half the amount. White pepper tends to have a stronger flavor that blooms more intensely that black pepper. So add it a little at a time and taste as you go.
Typically you would add white pepper if you wanted a pure white soup with no visual flecks of pepper. Since we are roasting the cauliflower in this recipe, we will get some color regardless.
Can I Freezer this Roasted Cauliflower Soup Recipe?
Yes, this cauliflower soup will freeze just fine and should last three months frozen. You may need to stir it with a whisk if any separation occurs during thawing. But as long as it is stored in an air tight container, there should be minimal flavor loss.
Can I use this roasted cauliflower soup recipe to make healthier mashed potatoes?
Yes! This cauliflower soup can be used in place of heavy cream and some butter in mashed potatoes. When doing this, a good ratio of potato to cauliflower soup to start with is half a cup of soup to one pound of potatoes ( 250 ml of soup per kg of potato). I still suggest adding some butter.
Can I I substitute a Dairy Alternative to make this Roasted Cauliflower Soup Recipe Vegan?
Absolutely! All you would need to do is replace the heavy cream and parmesan cheese. I would recommend a non-flavored and unsweetened nut milk. Almond milk works great. Since you are also removing the parmesan cheese, you will loose some of the umami flavors. Adding a half cup of mushrooms to the cauliflower soup recipe during the sweating aromatics step would be a good substitution.