StewsEuropeanEasy

Slow Cooker Sourdough Mushroom Barley Stew with Thyme Croutons

Name: Slow Cooker Sourdough Mushroom Barley Stew with Thyme Croutons
Prep time: 25 min
Cook time: 4 h
Total time: 4 h 25 min
Yield: 6 servings
Cuisine: European
Ingredients: 8 cups (1920 ml) vegetable broth; 1 cup (200 g) pearl barley, rinsed; 1½ lb (680 g) mixed mushrooms (cremini, oyster, shiitake), cleaned, cut into ¾-inch pieces; 2 medium (300 g) yellow onion, diced; 2 stalks (160 g) celery, diced; 2 large (260 g) carrot, peeled, diced into ½-inch pieces; 4 clove (20 g) garlic cloves, minced; 4 sprigs (8 g) fresh thyme sprigs; 2 leaf bay leaf; 2 tbsp (30 ml) olive oil; 1½ tsp (9 g) kosher salt; ½ tsp (1 g) freshly ground black pepper; 4 oz (115 g) sourdough bread, cut into ¾-inch cubes, slightly dried; 3 tbsp (45 ml) olive oil; 1½ tsp (1½ g) dried thyme; ½ tsp (3 g) kosher salt; ¼ tsp (½ g) garlic powder

From the MyKitchenBank Kitchen

A hearty vegetarian stew where pearl barley becomes creamy and tender in a slow cooker alongside earthy mixed mushrooms, caramelized onions, and aromatic herbs. Vegetable broth deepens into a rich, savory base. Served with crispy thyme-seasoned sourdough croutons for textural contrast and a rustic finish.

Prep: 25 min
Cook: 4 hr
Total: 4 hr 25 min
Makes: 6 servings (about 10 cups stew plus croutons)

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Ingredients

6 servings

For the stew
8 cups (1920 ml) vegetable broth
1 cup (200 g) pearl barley, rinsed
1½ lb (680 g) mixed mushrooms (cremini, oyster, shiitake), cleaned, cut into ¾-inch pieces
2 medium (300 g) yellow onion, diced
2 stalks (160 g) celery, diced
2 large (260 g) carrot, peeled, diced into ½-inch pieces
4 clove (20 g) garlic cloves, minced
4 sprigs (8 g) fresh thyme sprigs
2 leaf bay leaf
2 tbsp (30 ml) olive oil
1½ tsp (9 g) kosher salt
½ tsp (1 g) freshly ground black pepper
For the croutons
4 oz (115 g) sourdough bread, cut into ¾-inch cubes, slightly dried
3 tbsp (45 ml) olive oil
1½ tsp (1.5 g) dried thyme
½ tsp (3 g) kosher salt
¼ tsp (0.5 g) garlic powder

Equipment (7)

6-quart slow cooker
Large cutting board
Large knife
Medium bowl
Baking sheet (16×12 inch or larger)
Wooden spoon
Measuring cups and spoons

Steps

Before you start

Cube the sourdough bread for croutons 1–2 hours ahead so it can dry slightly
Use a 6-quart or larger slow cooker
Have all vegetables prepped and ready to go into the slow cooker

1
Sauté mushrooms and aromatics
- Heat 2 tbsp olive oil in a large skillet over medium-high heat.
- Once shimmering, add the diced mushrooms and cook for 6–8 minutes, stirring occasionally, until they release their liquid and begin to brown.
- The mushrooms should smell earthy and fragrant, with any excess liquid largely evaporated.
- Add the diced onion, celery, and carrot, and cook for another 3 minutes, stirring often, until the onion becomes translucent at the edges.
- Stir in the minced garlic and cook for 1 minute until fragrant.
- Season with 1.5 tsp salt and ½ tsp black pepper.
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Ready when: Mushrooms have released and reabsorbed their liquid; onion is translucent; garlic is fragrant
Tip: Don't skip sautéing the mushrooms—browning them develops umami depth that enriches the entire stew
2
Transfer to slow cooker
- Transfer the sautéed mushroom mixture to your 6-quart slow cooker.
- Add the rinsed pearl barley, vegetable broth, 4 fresh thyme sprigs, and 2 bay leaves.
- Stir well to combine.
- The barley should be submerged but does not need to be fully covered—the liquid will cook it through.
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Tip: Stir the slow cooker contents to ensure even distribution of barley and vegetables
3
Cook on low for 4 hours
- Cover the slow cooker and set to low heat.
- Cook for 4 hours, stirring once halfway through if you're around.
- The barley will gradually absorb the broth and become tender.
- Do not lift the lid frequently—each opening extends cooking time by 15–20 minutes.
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Ready when: Barley is tender and creamy; mushrooms are very soft; broth has thickened slightly and tastes deeply savory
Tip: Stir only once or twice during cooking to preserve heat and allow the barley to cook evenly
4
Make the croutons
- While the stew cooks, prepare the croutons.
- Toss the 4 oz sourdough bread cubes with 3 tbsp olive oil, 1.5 tsp dried thyme, ½ tsp kosher salt, and ¼ tsp garlic powder in a medium bowl until every cube is lightly coated.
- Spread in a single layer on a 16×12-inch baking sheet.
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Tip: Use slightly dried sourdough cubes (from 1–2 hours earlier) so they crisp rather than soften
5
Toast croutons in ovenOven 375°F / 190°C
- Preheat your oven to 375°F (190°C).
- Bake the croutons for 12–15 minutes, stirring once halfway through, until golden brown and crispy on the outside.
- The centers should still have a slight chew.
- Remove from the oven and let cool on the baking sheet for 2 minutes so they crisp further.
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Ready when: Croutons are golden brown and crispy on the outside
Tip: Don't overbake—croutons continue to crisp as they cool, and you want them crunchy, not hard
6
Finish and serve
- When the stew is done, remove the bay leaves and thyme sprigs.
- Taste and adjust seasoning with additional salt and pepper if needed.
- Ladle the hot stew into bowls and top each serving with a generous handful of warm thyme croutons.
- The croutons will soften slightly from the steam but retain their crunch.
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Tip: Add croutons just before serving so they stay crispy—they'll absorb the broth if left to sit

Good to know

Tips

Brown the mushrooms first to develop umami—raw mushrooms added to a slow cooker become mealy and bland
If your stew seems too thin after 4 hours, mix 1 tbsp cornstarch with 2 tbsp water and stir it in during the last 30 minutes of cooking, with the lid off
Use a mix of mushroom varieties if possible; cremini, oyster, and shiitake together create layers of earthy, nutty, and slightly smoky flavor
Save any leftover croutons to toss into salads or use as a garnish for soups—they're delicious for 2 days

Make ahead

Cube the sourdough bread and allow it to air-dry at room temperature for 1–2 hours. Prepare and refrigerate the mushroom, onion, celery, and carrot mixture up to 8 hours ahead; reheat gently in the skillet before adding to the slow cooker. Croutons are best made the day of serving for optimal crunch, though they keep in an airtight container for up to 2 days.

Storage & reheating

Stew keeps in an airtight container in the refrigerator for up to 4 days. Reheat gently in a pot over medium heat on the stovetop with a splash of vegetable broth or water to restore consistency. Freeze for up to 3 months in freezer-safe containers; thaw overnight in the refrigerator and reheat as above. Croutons should be stored separately in an airtight container at room temperature for up to 2 days, or frozen in an airtight bag for up to 1 month. Toast frozen croutons in a 350°F (175°C) oven for 4–5 minutes before serving.

Substitutions

pearl barley → farro or spelt berries. Use the same weight; farro cooks slightly faster (3½ hours on low), so check at 3 hours
mixed mushrooms (cremini, oyster, shiitake) → cremini mushrooms alone or a mix of cremini and button mushrooms. Use 1.5 lb total; the stew will be slightly less earthiness without the oyster and shiitake, but still deeply flavorful
sourdough bread → rustic whole-grain bread or day-old ciabatta. Cut into ¾-inch cubes and allow to dry; avoid soft white bread, which becomes mushy
fresh thyme sprigs → 2 tsp dried thyme sprinkled into the stew plus ½ tsp in the croutons. Dried thyme is more concentrated, so use less; add at the same time as the bay leaves