Vegetable Soup (Keto, No Potatoes, 5.4g Net Carbs)
- Total time
- 55 minutes
- Makes
- 10 servings
- Net carbs
- 5.4g
- Calories
- 76
Vegetable soup is the pot you make when the weather turns cold and the fridge is full of odds and ends. Onion, celery and carrot go into butter, the broth goes in, and half an hour later there is a big pot of something warm that feeds everyone for days.
The classic version leans on potatoes, corn and peas, and that is where the carbs come from. A typical recipe lists about 30g of carbs a serving. This one keeps the tomato broth and the hearty feel and swaps the starchy vegetables for cauliflower, green beans and spinach. A generous bowl comes to 5.4g net carbs.
It is a simple soup, and two small things decide how good it is. Cook the onion, celery, carrot and garlic in fat first, because raw vegetables boiled in broth taste flat. And add the spinach at the very end, so it stays green instead of turning dull and stringy.
Why This Keto Vegetable Soup Works
Cauliflower stands in for the potatoes. Chopped small, it turns tender in the same 25 minutes and soaks up the broth the way potato cubes do, for a fraction of the carbs.
Carrots stay, in a small amount. Two carrots across ten servings add sweetness and color without moving the carb count much. A soup with no carrot at all tastes like something is missing.
Beef broth and Worcestershire sauce give it depth. There is no meat in the pot, so the broth has to carry the flavor. A tablespoon of Worcestershire sauce adds the savory note that makes it taste slow-cooked.
Canned tomatoes do the rest. Two cans of diced tomatoes, juice and all, turn plain broth into a real soup base.
Recipe Overview
- Prep Time: 15 minutes
- Cook Time: 40 minutes
- Total Time: 55 minutes
- Serves: 10 (about 1¼ cups each)
- Net Carbs: 5.4g per serving
Ingredients
| Ingredient | Quantity | Notes |
| Butter | 1 tbsp | |
| Olive oil | 1 tbsp | |
| Onion | 1 medium | Chopped |
| Celery | 3 stalks | Chopped |
| Carrots | 2 | Peeled and chopped |
| Garlic | 4 cloves | Minced |
| Cauliflower florets | 2 cups | Chopped small |
| Fresh green beans | 1½ cups | Trimmed, cut into 1-inch pieces |
| Canned diced tomatoes | 2 cans (14.5 oz each) | With their juice |
| Beef broth | 8 cups | |
| Worcestershire sauce | 1 tbsp | |
| Italian seasoning | 1 tbsp | |
| Salt | 1 tsp | Plus more to taste |
| Cracked black pepper | 1 tsp | |
| Fresh spinach | 2 cups |
Cut everything to about the same size. Half-inch pieces of carrot, celery and cauliflower cook evenly and fit on a spoon together. Big florets take longer than the rest of the pot.
Check the tomato label. Plain diced tomatoes should list tomatoes, juice and salt. Some seasoned or stewed kinds have added sugar.
Choose your broth with the salt in mind. Regular beef broth is salty, and the recipe adds a teaspoon of salt at the end. With regular broth, taste first and add the salt a little at a time. Low-sodium broth gives you more control.
Recipe Timing
| Stage | Time |
| Chop the vegetables | 15 minutes |
| Soften the onion, celery, carrots and garlic | 5 minutes |
| Bring the pot to a boil | 8 to 10 minutes |
| Simmer until the vegetables are tender | 25 minutes |
| Season and wilt the spinach | 1 to 2 minutes |
| Total | About 55 minutes |
How to Make Vegetable Soup, Step by Step
1. Melt the butter with the oil
Set a large stock pot or Dutch oven over medium heat. Add the butter and olive oil and let the butter melt. You need a pot that holds at least 5 quarts, because 8 cups of broth and all the vegetables go in.
2. Soften the aromatics
Add the onion, celery, carrots and garlic. Cook for 5 minutes, stirring often, until the onion turns soft and glossy. Keep the heat at medium so the garlic does not brown. This short step builds most of the flavor in the pot.
3. Add everything except the spinach
Add the cauliflower florets, green beans, diced tomatoes with their juice, beef broth, Worcestershire sauce and Italian seasoning. Stir well and scrape the bottom of the pot.
4. Boil, then simmer
Turn the heat up and bring the soup to a boil. Then lower it to a gentle simmer and cook for 25 minutes, or until the vegetables are tender. Test a piece of carrot and a green bean. They are the slowest to soften, so when they are done, everything is done.
5. Season and add the spinach
Stir in the salt and pepper, then add the spinach. Cook for 1 to 2 minutes, just until the leaves wilt. Take the pot off the heat right away so the spinach stays bright.
6. Taste and serve
Taste the broth and add more salt and pepper if it needs it. Ladle into bowls and serve hot.
Tips and Variations
- Do not skip the sauté. Five minutes in butter and oil is the difference between a soup that tastes cooked and one that tastes boiled.
- Keep it at a simmer. A hard boil for 25 minutes breaks the cauliflower into crumbs and clouds the broth.
- Want it heartier? Chopped turnips are a good stand-in for potatoes. Add them with the cauliflower. They will add a few carbs.
- Swap the vegetables. Any low-carb vegetable works here. Zucchini and red bell pepper are both good additions.
- Make it vegetarian. Use vegetable broth and leave out the Worcestershire sauce, which contains anchovies.
- Add protein. Stir in cooked, shredded chicken at the end and warm it through. For a beef version, our keto hamburger soup is built on the same kind of tomato broth.
- Add heat or herbs. A pinch of crushed red pepper flakes or a bay leaf in the simmer both work. Chopped fresh parsley on top is a nice finish.
What to Serve With Vegetable Soup
On its own, a bowl of this soup is light: about 76 calories. That makes it a good starter, or a side for a richer main dish. To turn it into lunch, add something with fat and protein next to it.
Bread or saltines are the usual partner. For a low-carb table, a handful of keto crackers gives you the same crunch for dipping. A spoonful of grated Parmesan on top or a few slices of cheese on the side also help the bowl feel like a meal.
Storage and Reheating
Fridge: let the soup cool completely, then store it in airtight containers for up to 5 days. The flavor deepens by the next day.
Freezer: the soup freezes well for up to 3 months. There is no cream or pasta in it to split or go soft. Leave a little room at the top of each container, because the broth expands as it freezes.
Reheat: thaw overnight in the fridge, then warm the soup in a pot over medium heat until it is hot all the way through. A single bowl reheats well in the microwave.
Frequently Asked Questions
Is vegetable soup keto?
It depends on the vegetables. Potatoes, corn and peas make a regular bowl high in carbs. This recipe uses cauliflower, green beans and spinach instead and keeps the carrots small, which brings a 1¼-cup serving to 5.4g net carbs.
Which vegetables are best for a low-carb soup?
Cauliflower, green beans, celery, spinach, zucchini and bell pepper are all low in carbs and hold up in broth. Onion, carrot and tomato have more, so they are used in smaller amounts for flavor.
Can I use frozen vegetables?
Fresh vegetables are what this recipe was written for. Frozen green beans and frozen cauliflower should work as well. They are already partly cooked, so start checking them a few minutes early.
How do I make the broth richer?
Start with a good beef broth, do not skip the Worcestershire sauce, and give the onion, celery, carrot and garlic their full 5 minutes in the butter and oil. If the finished soup still tastes thin, it almost always needs a little more salt.
More Low-Carb Soups
- Easy Cabbage Soup — cabbage simmered with fire-roasted tomatoes and herbs in vegetable broth.
- Italian Wedding Soup — small all-beef meatballs and kale in chicken broth, 5.8g net carbs.
- Stuffed Pepper Soup — ground beef and bell peppers with cauliflower rice in place of the rice.
- French Onion Soup — slowly caramelized onions under melted Gruyere, with no bread.
- Cheeseburger Soup — ground beef and sharp cheddar in a creamy broth, with no potatoes.
Recipe Card
The full ingredient list and the method in short are in the card below.
Keto Vegetable Soup
Equipment
- Large stock pot or Dutch oven 5 quarts or larger
- Ladle
Ingredients
- 1 tbsp butter
- 1 tbsp olive oil
- 1 medium onion chopped
- 3 stalks celery chopped
- 2 carrots peeled and chopped
- 4 cloves garlic minced
- 2 cups cauliflower florets chopped small
- 1 1/2 cups fresh green beans trimmed, cut into 1-inch pieces
- 2 cans (14.5 oz each) canned diced tomatoes with their juice
- 8 cups beef broth
- 1 tbsp Worcestershire sauce
- 1 tbsp Italian seasoning
- 1 tsp salt plus more to taste
- 1 tsp cracked black pepper
- 2 cups fresh spinach
Instructions
- Melt: Heat the butter and olive oil in a large stock pot over medium heat until the butter has melted.
- Soften: Add the onion, celery, carrots and garlic. Cook for 5 minutes, stirring often.
- Add: Add the cauliflower florets, green beans, diced tomatoes with their juice, beef broth, Worcestershire sauce and Italian seasoning. Stir to combine.
- Simmer: Bring to a boil, reduce to a simmer and cook for 25 minutes, or until the vegetables are tender.
- Finish: Season with the salt and pepper and add the spinach. Stir and cook for 1 to 2 minutes, until the spinach has wilted.
- Serve: Taste, add more salt and pepper if needed, and serve hot.
Notes
Keep cooking
