Slow Cooker Chicken Celery Root and Thyme Soup

Name: Slow Cooker Chicken Celery Root and Thyme Soup
Prep time: 20 min
Cook time: 8 h
Total time: 8 h 20 min
Yield: 6 servings
Cuisine: French
Ingredients: 1¾ lbs (800 g) boneless, skinless chicken breasts, patted dry; 1 large bulb (500 g) celery root (celeriac), peeled and cut into 1-inch cubes; 2 medium (350 g) leeks, white and light green parts only, halved lengthwise, rinsed, and cut into 1-inch pieces; 12 oz (340 g) Yukon Gold potatoes, peeled and cut into ¾-inch cubes; 6 cups (1440 ml) low-sodium chicken broth; 6 sprigs (12 g) fresh thyme sprigs; 1 bay leaf; kosher salt, to taste; freshly ground black pepper, to taste; ½ cup (120 ml) heavy cream; 1½ tbsp (21 g) unsalted butter (optional); 2 tbsp (8 g) fresh flat-leaf parsley, finely chopped, for garnish (optional)

From the MyKitchenBank Kitchen

A French-American inspired slow cooker soup combining tender poached chicken with earthy celery root, delicate leeks, and potatoes finished with cream and fresh thyme. The long, gentle cooking renders the vegetables silky and creates a naturally rich broth without any additional stock—perfect for cool weather meals.

Prep: 20 min
Cook: 8 hr
Total: 8 hr 20 min
Makes: 6 servings (about 8 cups)

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Ingredients

6 servings

1¾ lbs (800 g) boneless, skinless chicken breasts, patted dry
1 large bulb (500 g) celery root (celeriac), peeled and cut into 1-inch cubes
2 medium (350 g) leeks, white and light green parts only, halved lengthwise, rinsed, and cut into 1-inch pieces
12 oz (340 g) Yukon Gold potatoes, peeled and cut into ¾-inch cubes
6 cups (1440 ml) low-sodium chicken broth
6 sprigs (12 g) fresh thyme sprigs
1 bay leaf
kosher salt, to taste
freshly ground black pepper, to taste
½ cup (120 ml) heavy cream
1½ tbsp (21 g) unsalted butter (optional)
2 tbsp (8 g) fresh flat-leaf parsley, finely chopped, for garnish (optional)

Equipment (8)

6-quart (5.7 L) slow cooker
Chef's knife
Cutting board
Measuring cups and spoons
Tongs
Immersion blender or regular blender (optional)
Ladle
Meat thermometer (optional but recommended)

Steps

Before you start

Trim and thoroughly rinse leeks by slicing lengthwise and checking between layers for grit
Cut all vegetables roughly to size so they cook evenly
Pat chicken breasts dry to help them cook more evenly
Have your slow cooker ready and on the counter

1
Arrange chicken and vegetables
- Add the patted-dry chicken breasts to the bottom of a 6-quart slow cooker.
- Scatter the celery root cubes, leek pieces, and potato cubes around and over the chicken.
- Tuck the thyme sprigs and bay leaf among the vegetables.
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Tip: Don't overcrowd the slow cooker; arrange ingredients in a single layer where possible so they cook evenly.
2
Pour broth and season
- Pour the chicken broth over everything until vegetables are just covered—you may not need all of it depending on your slow cooker's shape.
- Season with ½ teaspoon kosher salt and ¼ teaspoon black pepper.
- Stir gently to combine.
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Tip: Err on the side of less salt now since the broth reduces slightly; you can adjust after cooking.
3
Cook on low 8 hours
- Cover the slow cooker and cook on low heat for 8 hours.
- The chicken will poach gently and the vegetables will become completely tender and start to break down slightly, enriching the broth naturally.
- Do not stir during cooking.
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Ready when: Chicken registers 165°F (74°C) on an instant-read thermometer inserted into the thickest part; celery root is completely soft and nearly melting
Tip: Resist lifting the lid; each opening adds 15–20 minutes to cooking time.
4
Shred chicken and check vegetables
- After 8 hours, use tongs to carefully remove the chicken breasts and place on a cutting board.
- Let them cool for 2–3 minutes, then shred them with two forks into bite-sized pieces, discarding any bones or cartilage.
- Return the shredded chicken to the slow cooker.
- Stir gently; the soup should be quite thick because the vegetables have broken down and released their starches.
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Ready when: Chicken shreds cleanly, vegetables break apart easily when stirred
Tip: Don't worry if some celery root and potato have disintegrated into the broth—this is intentional and adds body and creaminess.
5
Blend partially (optional)
- For a silkier soup, use an immersion blender to partially blend the broth and vegetables, pulsing for 10–15 seconds until some vegetable pieces remain but the texture is creamier.
- Alternatively, carefully transfer 2 cups of the hottest broth and some vegetables to a regular blender, blend until smooth, and return to the slow cooker.
- This step is optional; you can serve it chunky if preferred.
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Ready when: Soup is flecked with vegetable pieces but noticeably creamier
Tip: Leave some texture; over-blending makes it taste more like purée than rustic soup.
6
Stir in cream and butter
- Pour the heavy cream into the slow cooker and stir gently until combined.
- If using butter, add it now and let it melt into the hot soup, stirring occasionally for 1 minute.
- The soup will taste rich and velvety.
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Ready when: Cream is fully incorporated and soup looks uniform in color
Tip: Butter is optional but adds a silky mouthfeel; stir it in gently to avoid breaking the emulsion.
7
Taste and adjust seasoning
- Taste a spoonful carefully and add more salt and black pepper as needed.
- The soup should taste savory with subtle anise notes from the thyme and a mild earthiness from the celery root.
- Remove and discard the bay leaf and any remaining thyme stems if they're easy to fish out.
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Ready when: Flavors are balanced and pleasant when tasted
Tip: Add salt gradually and taste between additions; it's easy to oversalt, harder to fix.
8
Ladle and garnish
- Using a ladle, divide the soup among six bowls.
- Top each bowl with a pinch of fresh chopped parsley and a grind of black pepper.
- Serve hot with crusty bread on the side if desired.
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Tip: Garnish just before serving so the parsley stays bright green and fragrant.

Good to know

Tips

Prep all vegetables the night before and store them in separate containers in the refrigerator. In the morning, add them straight to the slow cooker—this saves 15 minutes of active time.
If your slow cooker runs hot, start checking the chicken at 7 hours; some models cook faster than others. It should shred easily but still be moist, not stringy.
For a deeper flavor, brown the chicken in a hot skillet with a pinch of salt for 3–4 minutes per side before adding to the slow cooker. This adds color and caramelized depth but increases prep time to 25 minutes.
Celery root can discolor quickly after cutting; toss the prepared pieces with a squeeze of lemon juice and a pinch of salt if prepping more than 1 hour ahead, then drain before adding to the slow cooker.

Make ahead

This soup improves after a day or two in the refrigerator as flavors deepen. Prepare it fully through step 7, cool completely, and refrigerate. Reheat gently on the stovetop over medium-low heat, stirring occasionally, for 8–10 minutes. Do not boil or the cream may separate.

Storage & reheating

Refrigerator: Store in an airtight container for up to 4 days. Freezer: This soup freezes well for up to 3 months (the vegetables and cream hold up better than some soups). Thaw overnight in the refrigerator and reheat gently on the stovetop over medium-low heat, adding a splash of chicken broth or water if the soup seems too thick. Room temperature: Do not leave out for more than 2 hours.

Substitutions

celery root (celeriac) → parsnips or a combination of parsnips and celery root (use 500 g total). Parsnips are slightly sweeter; use them if celery root is unavailable. The flavor will shift from earthy to subtly sweet.
heavy cream → half-and-half or whole milk (120 ml). The soup will be less rich but still creamy. Use half-and-half for a middle ground or milk for a lighter version.
fresh thyme sprigs → 1 teaspoon dried thyme, added in step 2. Dried thyme is more concentrated; use about one-third the amount. Add it at the start since it needs time to infuse.
boneless, skinless chicken breasts → boneless, skinless chicken thighs (900 g total, about 4–5 thighs). Thighs are fattier and stay more tender; use about the same weight. Cooking time remains 8 hours on low.