Slow Cooker Roasted Celeriac Root with Crispy Mustard Seed Oil Amaranth

Name: Slow Cooker Roasted Celeriac Root with Crispy Mustard Seed Oil Amaranth
Prep time: 20 min
Cook time: 45 min
Total time: 1 h 5 min
Yield: 4 servings
Cuisine: European
Ingredients: 1½ lb (680 g) celeriac root, peeled, cut into 1-inch cubes; 1¼ cups (300 ml) vegetable or light chicken broth; ¼ cup (60 ml) dry white wine; 1 whole (75 g) shallot, large, sliced thin; 4 cloves (20 g) garlic cloves, minced; 4 sprigs (8 g) fresh thyme sprigs; 1 whole (½ g) bay leaf; ½ tsp (2½ g) coriander seeds, lightly crushed; 6 whole (1½ g) black peppercorns; to taste sea salt; ¾ cup (130 g) amaranth grains, rinsed; 2 tbsp (20 g) brown mustard seeds; ⅓ cup (80 ml) extra-virgin olive oil; 3 cloves (15 g) garlic cloves, sliced thin, sliced thin; ¼ tsp (½ g) red pepper flakes (optional); 3 tbsp (15 g) fresh flat-leaf parsley, chopped, chopped; ½ tsp (2 g) lemon zest, finely grated

From the MyKitchenBank Kitchen

Tender, caramelized celeriac slowly cooks in a warm spice bath while amaranth grains are finished in a mustard seed-infused oil with crispy seeds and aromatic garlic. Together they create a sophisticated vegetable-and-grain side with nutty depth and pleasant texture contrast—perfect alongside roasted meats or as a vegetarian main.

Prep: 20 min
Cook: 45 min
Wait: 4 hr 30 min
Total: 5 hr 35 min
Makes: 4 servings (about 1¼ cups each)

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Ingredients

4 servings

1½ lb (680 g) celeriac root, peeled, cut into 1-inch cubes
1¼ cups (300 ml) vegetable or light chicken broth
¼ cup (60 ml) dry white wine
1 whole (75 g) shallot, large, sliced thin
4 cloves (20 g) garlic cloves, minced
4 sprigs (8 g) fresh thyme sprigs
1 whole (0.5 g) bay leaf
½ tsp (2.5 g) coriander seeds, lightly crushed
6 whole (1.5 g) black peppercorns
to taste sea salt
¾ cup (130 g) amaranth grains, rinsed
2 tbsp (20 g) brown mustard seeds
⅓ cup (80 ml) extra-virgin olive oil
3 cloves (15 g) garlic cloves, sliced thin, sliced thin
¼ tsp (0.5 g) red pepper flakes (optional)
3 tbsp (15 g) fresh flat-leaf parsley, chopped, chopped
½ tsp (2 g) lemon zest, finely grated

Equipment (6)

4–5 quart slow cooker
Sharp chef's knife or vegetable peeler
Small saucepan
Large spoon or spatula
Measuring cups and spoons
Cutting board

Steps

Before you start

Peel the celeriac fully and cut into even 1-inch cubes so they cook uniformly
Rinse amaranth under cold water to remove any debris
Have all spices measured and ready before starting
Plan for 4.5 hours in the slow cooker—cook on low

1
Build the slow cooker base
- Add the cubed celeriac to a 4–5 quart slow cooker along with the broth, white wine, sliced shallot, minced garlic, thyme sprigs, bay leaf, crushed coriander seeds, and black peppercorns.
- Stir gently to combine and season lightly with sea salt.
- Cover and set to low heat.
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Tip: Cut celeriac into uniform 1-inch pieces so they all cook at the same rate and become tender without falling apart.
2
Slow cook celeriac until tender
- Cook the celeriac on low for 4 hours.
- The cubes should be completely tender when pierced with a fork, with the edges beginning to soften but still holding their shape.
- The braising liquid will be aromatic with coriander and thyme.
- Do not stir during cooking.
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Ready when: Celeriac cubes are fork-tender and edges soften slightly
Tip: Resist the urge to open the lid—every peek adds 15–20 minutes to cooking time.
3
Toast and bloom mustard seeds
- About 30 minutes before the celeriac finishes (after 3.5 hours), warm the olive oil in a small saucepan over medium heat.
- Add the brown mustard seeds and sliced garlic cloves.
- Toast for 2–3 minutes, stirring frequently, until the seeds begin to crackle and pop loudly and smell nutty and slightly spicy.
- Add the red pepper flakes if using.
- Remove from heat and set aside.
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Ready when: Mustard seeds pop and crackle; garlic is golden and fragrant
Tip: Listen for the crackling sound—it signals the seeds are fully toasted. Don't let them burn or they'll taste bitter.
4
Cook amaranth in broth
- In the same saucepan or a fresh one, bring 2 cups (480 ml) of vegetable broth to a boil.
- Stir in the rinsed amaranth grains, reduce heat to low, and simmer covered for 18–20 minutes.
- The amaranth is done when all the liquid is absorbed and the grains are tender with a slight nuttiness, and you can see the little spiral germ at the grain's center.
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Ready when: All liquid is absorbed, grains are tender and fluffy
Tip: Use a lid or cover to prevent evaporation. Amaranth can foam slightly—this is normal.
5
Finish celeriac and strain
- When the celeriac has finished cooking (after 4 hours total), check the seasoning and adjust with additional sea salt if needed.
- Using a slotted spoon, transfer the celeriac cubes to a serving bowl, leaving most of the braising liquid behind.
- Discard the thyme sprigs and bay leaf.
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Tip: Reserve a few tablespoons of braising liquid if the celeriac seems very dry; fold it in gently to add moisture.
6
Combine and finish with mustard oil
- Fluff the cooked amaranth with a fork and fold it gently into the celeriac.
- Pour the warm mustard seed oil over the top, including the crispy garlic slivers and popped seeds.
- Toss very gently to combine, being careful not to break up the tender celeriac.
- Season to taste with additional sea salt.
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Tip: The mustard oil will pool slightly at the bottom—this is intentional and adds flavor with every bite.
7
Garnish and serve
- Divide the celeriac and amaranth mixture among serving bowls or plates.
- Scatter the fresh chopped parsley and lemon zest over the top.
- Serve warm as a side dish or as a light vegetarian main with crusty bread and a simple green salad.
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Tip: Add the parsley just before serving so it stays bright green and fresh.

Good to know

Tips

Celeriac browns beautifully and becomes creamy in the slow cooker—this slow cooking method is far superior to quick sautéing for developing its natural sweetness.
The timing is designed so the amaranth finishes cooking just as the celeriac is done, then both are combined while warm so flavors meld.
Amaranth is a complete protein containing all nine amino acids, making this dish hearty and satisfying even without meat.
The mustard seed oil is the signature element—don't skip it or use pre-made mustard oil, as toasting the seeds fresh creates incomparable flavor and texture.

Make ahead

Prepare the celeriac cubes up to 1 day ahead and store them covered in the refrigerator. The slow cooker work can be done entirely the day before; reheat gently on low in the slow cooker for 30 minutes, then finish with the mustard seed oil just before serving.

Storage & reheating

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in a skillet over medium-low heat with a splash of broth, stirring occasionally, for about 5 minutes. The dish does not freeze well due to the texture of both the celeriac and amaranth.

Substitutions

amaranth grains → farro, spelt berries, or pearl barley (use the same weight; cooking time may increase to 25–30 minutes). These grains have a similar nutty flavor and chewy texture; adjust cooking time as needed.
celeriac root, peeled → parsnips or rutabaga, peeled and cut into 1-inch cubes. Both have a natural sweetness and will caramelize similarly in the slow cooker. Reduce cooking time to 3–3.5 hours for parsnips.
brown mustard seeds → cumin seeds or fennel seeds, toasted and ground. Provides different spice notes but maintains the toasted-seed oil concept. Use 1 tablespoon of whole seeds, toasted and lightly ground.
dry white wine → additional vegetable broth or vermouth. Maintains acidity and depth without the wine; use the same amount.