Keto Broccoli Cheese Soup

⏲ ~50 min total · prep 15 · cook 35 · 4 servings

By the KFI Test Kitchen · Tested & approved by Jason Lieu, KFI recipe editor

Published Sep 15, 2026 · Updated Sep 15, 2026

Ingredients

• 4 tbsp butter
• 1 small yellow onion, diced (about 3/4 cup)
• 3 cloves garlic, minced
• 5 cups broccoli florets (about 1 1/2 lbs), chopped into 1-inch pieces
• 3 cups chicken broth
• 1 cup heavy cream
• 4 oz cream cheese, cubed and softened
• 2 cups sharp cheddar, shredded by hand
• 1/4 tsp xanthan gum
• 1 tsp Dijon mustard
• 1/2 tsp each salt and black pepper

Instructions

1. Melt the butter in a 4-quart Dutch oven over medium and cook the onion 5 minutes, until the edges turn translucent; add the garlic for the last 30 seconds.
2. Pour in the broth and bring to a simmer, then add the broccoli, cover, and cook 8 minutes, until the stems give easily to a fork.
3. Blend right in the pot with an immersion blender, pulsing 6-8 times — leave half the broccoli in pea-size pieces so the soup has texture, not baby-food smooth.
4. Drop the heat to medium-low and stir in the cream and cubed cream cheese until fully melted, about 3 minutes; keep it below a simmer from here on.
5. Toss the cheddar with the xanthan gum in a dry bowl (this stops clumping), then add it one handful at a time, stirring until each handful melts before the next.
6. Off the heat, stir in the Dijon, salt, and pepper and let the soup stand 5 minutes — it should coat the back of a spoon before it goes to the bowl.

Why this recipe works

• Partial blend Six to eight pulses leave half the broccoli in pea-size pieces. That is what gives the soup body, instead of the strained, baby-food texture most blended soups fall into.
• Xanthan on the cheese Tossing the shredded cheddar with xanthan gum before it meets the pot stops the shreds from clumping. Each handful melts in clean.
• Cream cheese buffer Cream cheese melts below a simmer and steadies the whole dairy base. It is the reason the pot can sit warm without splitting.

Tips for making this recipe well

Cut to one inch

Even pieces mean the stems and florets soften at the same time. Random sizes leave crunchy stems floating in a pot of overcooked tops.

Stay under a simmer

Once the cream and cream cheese go in, keep the heat at medium-low. A full boil can split the soup, and no amount of stirring fully fixes the texture after that.

Grate the cheddar yourself

Pre-shredded bags carry anti-caking starch that fights melting. A block grated coarse melts into the base with far fewer grainy bits.

The spoon test

Five minutes off the heat, the soup should coat the back of a spoon. If it still runs thin, give it a few more minutes; xanthan keeps thickening as it stands.

You can over-blend

Pulse, stir, and check between bursts. Blending is the one step here you cannot undo.

Serving suggestions

Ladle the soup into warmed bowls while it still coats the back of a spoon. A pinch of cheddar on top melts into a soft cap within a minute, and a few grinds of black pepper play against the Dijon already stirred in. At 14.7 net carbs a serving, this is a filling lunch on its own; the cream and a pound and a half of broccoli see to that. Warm bowls matter. Cold ceramic thickens the cheese coating faster than you want, and the first spoonful suffers for it.

Storage and meal prep

Cool the pot on the counter, then refrigerate covered for 3 to 4 days. The xanthan and cheese keep binding as it sits, so expect it noticeably thicker tomorrow; loosen with a splash of broth while reheating. Warm it over medium-low and stir often, holding it under a simmer so the dairy stays smooth. Freezing for up to 2 to 3 months works, though thawed soup turns slightly grainy. A short blend with the immersion blender while it reheats pulls the texture most of the way back.

Variations worth trying

• Bacon top Crisp chopped bacon first, cook the onion in the rendered fat, and scatter the pieces over each bowl.
• Half cauliflower Swap one cup of the broccoli for cauliflower florets; the partial blend hides the difference.
• Pepper jack pot Replace half the cheddar with shredded pepper jack for a gentler heat that carries through the cream.
• Roasted florets Roast the broccoli at high heat until browned at the edges, then simmer it briefly in the broth. The pot turns deeper and nuttier.

Frequently asked questions

Why toss the cheddar with xanthan gum?

Dry shredded cheese clumps when it hits hot liquid, and xanthan around each shred keeps them apart. You get a smooth melt instead of cheese balls in the pot.

Can I use frozen broccoli florets?

Yes. Thaw and pat them dry first, and expect a slightly softer texture, since frozen florets break down faster in the simmer.

My soup turned grainy. What went wrong?

Usually a boiled pot. Once the cream, cream cheese, and cheddar are in, everything stays below a simmer. Bagged shreds can do it too.

No immersion blender?

Use a countertop blender in batches, filling the jar no more than halfway and venting the lid. Pour it back into the pot, leave some chunks, and continue with the cream.

How many net carbs are in a serving?

14.7 net carbs, mostly from the broccoli and the onion. The cream, cream cheese, and cheddar carry almost none.

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