Sautéed leeks and onion, cubed Russet potatoes, vegetable stock, and a bay leaf go into the slow cooker for six hours. Double cream and a pass with a hand-held blender finish the soup before serving. One batch makes 4 servings, ready in 6 hours on high or 8 hours on low.

The leeks and onion go into a hot pan first, not straight into the pot. That sauté in butter and oil removes the harsh raw edge both carry, which slow cooking alone cannot replicate. Adding them raw means the soup simmers all day but still tastes flat and vegetal when served.

Russet potatoes are the variety this recipe relies on for both natural thickening and a smooth blend. The starch they release into the stock as they cook thickens the soup without any added flour or cornflour. Waxy varieties stay firm and resist the blender, leaving the finished soup gritty rather than smooth.

Slow Cooker Leek and Potato Soup

Recipe by Shili MohamedCourse: SoupsCuisine: BritishDifficulty: Easy

Servings

4

servings

Prep time

15

minutes

Cooking time

6

hours 

Calories

262

kcal

Slow Cooker Leek and Potato Soup with sautéed leeks and Russet potatoes, simmered in vegetable stock and finished with cream. Serves 4, ready in 6 hours

Ingredients

• Soup

• 15g unsalted butter (1 tablespoon)

• 1 tablespoon olive oil

• 80g yellow onion, diced (about ½ cup)

• 360g leeks, white and light green parts only, thinly sliced (about 4 cups)

• 1 tablespoon garlic, minced (2 cloves)

• 450g floury potatoes (Russet or Maris Piper), peeled and cut into 2.5cm cubes

• 950ml unsalted vegetable stock

• 1½ teaspoons salt

• 1 bay leaf

• 3 sprigs fresh thyme

• 120ml double cream, plus extra to serve

• ¼ teaspoon black pepper

• 1 tablespoon fresh chives, chopped

Directions

• Heat a large frying pan over medium heat. Add the butter and olive oil. Once hot, add the diced onion and cook for 2 minutes until fragrant.
• Add the sliced leeks and cook for 5 to 7 minutes, stirring frequently, until softened and very lightly golden. Add the garlic and cook for a further 30 seconds. Transfer the sautéed vegetables to the slow cooker.
• Add the potatoes, vegetable stock, salt, bay leaf, and thyme sprigs to the slow cooker. Place the lid on and cook on HIGH for 4 to 6 hours or LOW for 6 to 8 hours, until the potatoes are tender when pierced with a fork.
• Discard the bay leaf and thyme sprigs.
• Blend the soup using a hand-held blender until smooth. Stir in the double cream and black pepper and taste to adjust seasoning. Ladle into bowls and finish with a drizzle of cream and a scattering of chopped chives.

FAQs

Can the cream be replaced to make the soup dairy-free?

Leaving out the cream and replacing it with full-fat coconut milk produces a rich finish without any dairy. The coconut flavour is mild enough at 120ml that it does not compete with the leek and thyme. Oat cream at the same quantity also works and gives a neutral flavour closer to the original.

What can be added for extra body and texture?

Crisp bacon lardons scattered over each bowl add a salty bite and contrast to the smooth soup. Grated mature Cheddar stirred in just before serving thickens the soup slightly and deepens the savoury base. A slice of crusty bread on the side turns the bowl into a full dinner with no other changes needed.

Can the HIGH setting be swapped for LOW throughout?

The LOW setting at 6 to 8 hours gives the same result as HIGH at 4 to 6 hours. LOW is useful when the soup needs to go on early in the morning and will not be served until the evening. The vegetables soften and the starch releases at either setting; only the timeframe changes.

What other slow cooker potato soup fits naturally alongside this one?

A second potato soup night fits naturally on the same weekly rotation as this bowl. A slow cooker creamy potato soup on this site takes the same potato base in a slightly richer direction. Together the two cover two versions of potato soup for back-to-back slow cooker nights.

What other creamy blended slow cooker soup pairs well with this one?

Not every slow cooker soup needs a long ingredient list to produce a rich, blended finish. A slow cooker cream of mushroom soup on this site uses the same blended approach with a deeply savoury base. Together the two give two creamy blended soups from one pot, with no extra equipment needed for either.