A Cajun-seasoned potato soup with andouille, built on the trinity of onion, celery and bell pepper.
Six hours on Low, then about twenty minutes of finishing that turns a pot of broth and potatoes into something genuinely creamy.
Why This Recipe Works
- Onion, celery and bell pepper is the Cajun trinity, and using bell pepper rather than the carrot a French mirepoix would use is what makes this taste regional rather than generic.
- Russets are the right potato here precisely because they fall apart — a third of them are meant to be mashed into the soup, and a waxy potato would resist.
- Andouille is already smoked and cooked, so the optional browning in step 1 is purely about the drippings it leaves for everything else to cook in.
- Holding back half the cheddar and most of the green onions for the bowl means the top of the soup has sharpness and bite that a fully stirred-in version loses.
Three Thickeners, In Order
Most creamy soups pick one way to thicken. This one uses three, in a deliberate sequence, and each is doing something the next cannot.
Mashed potato, first and freeRoughly one-third, lightly mashed
About a third of the potatoes crushed against the side of the crock. It costs nothing, adds no new flavour and thickens with the ingredient already in the pot — which is why it comes before reaching for anything else.
Cream cheese, for body not just thicknessFully melted, no lumps
Four ounces stirred in until melted. It thickens, but what it really adds is a rounded richness that starch on its own cannot produce. It goes in before the slurry because it needs the pot loose enough to disperse.
Cornstarch slurry, last and adjustableCold water, mixed into the cream
Two tablespoons whisked with cold water and stirred into the heavy cream before both go in together. Adding the slurry through the cream rather than straight into the pot is what stops it seizing into strands.
Fifteen to twenty minutes on HighSilky and slightly thickened
The pot needs real heat for the cornstarch to activate — a slurry stirred into a cooling crock never thickens at all. This is also where the soup goes from cloudy to silky.
Ingredient Notes
- Andouille sausage
- A pound, sliced, marked optional but traditional. Cured and smoked, so it needs no cooking through — leaving it out makes the recipe vegetarian with vegetable broth.
- Russet potatoes
- Two pounds, peeled and in half-inch cubes. Starchy by design here, because a third of them are going to be mashed into the soup.
- Cajun seasoning
- Two teaspoons, with more to taste. Blends vary enormously in salt, which is why the recipe's own salt is 'a pinch' and the real seasoning happens at the end.
- Cornstarch slurry
- Two tablespoons with cold water, stirred into the heavy cream. Cold water and via the cream — both details are in step 5 and both prevent lumps.
How to Make It
Brown the andouille, optionally
In a skillet over medium heat, brown the sliced andouille in butter or oil for 3 to 4 minutes. Transfer it to the slow cooker, leaving the drippings.
Load the slow cooker
Add the onion, celery, bell pepper, garlic, potatoes, broth, Cajun seasoning, smoked paprika, thyme, bay leaf and a pinch of salt and pepper. Stir to combine.
Cook
Low for 6 to 7 hours or High for 3 to 4, until the potatoes are very tender.
Mash to thicken
Lightly mash about one-third of the potatoes right in the slow cooker to create a creamy base.
Add the cream cheese and slurry
Stir in the cream cheese until melted. Whisk the cornstarch with cold water, stir it into the heavy cream, then pour that into the cooker. Cook on High for 15 to 20 minutes until silky and slightly thickened.
Finish
Stir in 1/2 cup of the cheddar and most of the green onions, then taste and adjust with more Cajun seasoning, salt or pepper.
Serve
Serve hot with the remaining cheddar, extra green onions, bacon and a few dashes of hot sauce.
Success Tips
- Mash before you slurry. The free thickening comes first.
- Slurry into cold water and then into the cream, never straight into a hot pot.
- Give it the full 15 to 20 minutes on High — cornstarch needs heat to work.
- Season at the end. Cajun blends and andouille both bring their own salt.
Serving Ideas
Cheddar, green onions, crisp bacon and hot sauce. The hot sauce is the one to put on the table rather than in the pot, since Cajun blends vary so much in heat already.
Storage and Reheating
Refrigerate
Refrigerate up to 4 days. It sets thick when cold because of the potato and cornstarch together.
Freeze
Not recommended. Potatoes go grainy and a pot thickened with cream cheese and cream separates on thawing.
Reheat
Gently on the stove or on Low with a splash of broth, stirring well. Keep it below a boil.
Frequently Asked Questions
Can I make it vegetarian?
Yes. The andouille is optional in the ingredient list, and vegetable broth is an alternative. Lean a little harder on the smoked paprika to replace the smokiness the sausage would have brought.
It is still thin after the slurry.
Usually not enough heat or not enough time — cornstarch needs a genuinely hot pot and the full 15 to 20 minutes on High. Mashing more of the potato is the other lever and it is free. Failing both, a second small slurry works.
How do I make it hotter?
More Cajun seasoning is the obvious answer but watch the salt, since most blends are salt-heavy. Cayenne on its own, or hot sauce at the table, adds heat without adding salt with it.
