Gluten-Free Blackened Fish with Dirty Rice and Slaw

Why You’ll Love This Recipe

• All the Cajun flavor with a gluten-free spice blend that delivers a smoky, bold crust.
• Balanced plate: savory dirty rice, flaky blackened fish, and a bright, lemony slaw.
• Weeknight-friendly: one pan for fish, one pot for rice, and a quick no-cook slaw.
• Flexible: dairy-free and pescatarian options included, with clear substitutions.

Grocery List

• Produce: Onion, green bell pepper, celery, garlic, lemon, green cabbage, red cabbage, carrot, scallions, flat-leaf parsley.
• Dairy: Unsalted butter (or use avocado oil for dairy-free), mayonnaise (gluten-free).
• Pantry: Catfish or cod fillets; long-grain white rice; gluten-free chicken or vegetable stock; gluten-free andouille sausage; tomato paste; gluten-free Worcestershire or coconut aminos; olive oil; avocado oil; kosher salt; black pepper; bay leaf; honey; Dijon mustard (GF); gluten-free hot sauce; spices for GF blackening blend (sweet paprika, smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne, white pepper optional).

Full Ingredients

Blackened Fish

• 4 skinless catfish or cod fillets (6 oz each), patted very dry
• 3 tbsp unsalted butter, melted (sub avocado oil for dairy-free), plus 1 tbsp butter for the pan
• 1 tbsp avocado oil (for high-heat searing)
• 2 1/2 tbsp GF Cajun blackening spice (from blend below), plus 1/2 tsp for finishing if desired
• Lemon wedges, for serving

Gluten-Free Cajun Blackening Spice (makes about 3 tbsp)

• 1 tbsp sweet paprika
• 2 tsp smoked paprika
• 1 tsp garlic powder
• 1 tsp onion powder
• 1 tsp dried thyme
• 1 tsp dried oregano
• 1 tsp kosher salt
• 1/2 tsp cayenne pepper (adjust to heat)
• 1/2 tsp ground black pepper
• 1/4 tsp ground white pepper (optional)

Use certified gluten-free spices if needed.

Dirty Rice

• 1 cup long-grain white rice, rinsed until water runs clear
• 1 3/4 cups gluten-free chicken or vegetable stock
• 6 oz gluten-free andouille sausage, small dice (or 6 oz cremini mushrooms for pescatarian)
• 1 small yellow onion, small dice
• 1 green bell pepper, small dice
• 2 celery ribs, small dice
• 2 cloves garlic, minced
• 2 tbsp tomato paste (GF)
• 1 tsp gluten-free Worcestershire sauce or coconut aminos
• 1 bay leaf
• 2 tbsp avocado or olive oil
• 1/2 tsp kosher salt, plus more to taste
• 1/4 tsp black pepper
• 2 tbsp chopped flat-leaf parsley (stir in at the end)
• Optional: 1 tsp of the blackening spice for a smokier rice

Lemon–Cabbage Slaw

• 4 cups shredded green cabbage
• 1 cup shredded red cabbage
• 1 large carrot, julienned or coarsely grated
• 2 scallions, thinly sliced
• 1/4 cup chopped flat-leaf parsley
• 1 tsp lemon zest
• 3 tbsp fresh lemon juice
• 2 tbsp gluten-free mayonnaise (or plain Greek yogurt)
• 1 tsp Dijon mustard (gluten-free)
• 1 tsp honey
• 2 tbsp extra-virgin olive oil
• 1/2 tsp kosher salt and 1/4 tsp black pepper, or to taste

Step-by-Step Instructions

Step 1: Mix the spice and season the fish

In a small bowl, stir together all ingredients for the Gluten-Free Cajun Blackening Spice. Pat the fish very dry with paper towels for maximum crust. Brush both sides of each fillet with 2 tbsp of the melted butter (or avocado oil), then coat generously with 2 1/2 tbsp of the spice blend, pressing it on so it adheres. Set aside at room temperature for 10 minutes while you start the rice.

Step 2: Build the dirty rice base

Heat 2 tbsp oil in a medium saucepan over medium heat. Add the diced gluten-free andouille and cook, stirring, until browned and some fat renders, 3–4 minutes. Add onion, bell pepper, and celery with 1/2 tsp salt and 1/4 tsp pepper. Cook until softened and lightly golden, 5–7 minutes. Stir in garlic and tomato paste; cook 1 minute until fragrant.

Step 3: Simmer the rice

Stir in the rinsed rice to coat in the aromatics, 30 seconds. Add stock, bay leaf, and GF Worcestershire (or coconut aminos). Bring to a boil, reduce heat to low, cover, and simmer 15 minutes. Remove from heat and let stand, covered, 5 minutes. Do not lift the lid during cooking. Discard bay leaf. If you like it smokier, sprinkle in 1 tsp of the blackening spice and fluff with a fork.

Step 4: Make the lemon–cabbage slaw

In a large bowl, whisk lemon zest, lemon juice, mayo, Dijon, honey, olive oil, salt, and pepper until smooth. Add green and red cabbage, carrot, scallions, and parsley. Toss to coat. Adjust seasoning to taste and refrigerate until serving (the slaw benefits from at least 10 minutes to relax and crisp up).

Step 5: Preheat the skillet for blackening

Place a well-seasoned cast-iron skillet over medium-high heat for 3–4 minutes until very hot. Turn on ventilation and open a window—blackening creates intentional smoke. Have the remaining 1 tbsp butter and 1 tbsp avocado oil ready.

Step 6: Sear the fish to a blackened crust

Add the oil and remaining 1 tbsp butter to the hot skillet. When shimmering, lay in the fillets without crowding. Sear 2–3 minutes until the underside is deeply charred in spots. Carefully flip and cook another 2–3 minutes, basting with the pan butter. The fish is done when it flakes easily and reaches 145°F internal temperature. Transfer to a warm plate and rest 2 minutes.

Step 7: Finish, plate, and serve

Fluff the dirty rice and fold in the chopped parsley (and a pinch of reserved spice if you like). Spoon a generous bed of rice onto plates, top with a fillet, and add a mound of lemon–cabbage slaw. Serve immediately with lemon wedges and gluten-free hot sauce.

Pro Tips

• Dry fish equals better crust: moisture fights browning, so pat thoroughly before seasoning.
• Heat matters: the skillet must be very hot before the fish goes in; otherwise the spices won’t blacken, they’ll steam.
• Rinse rice until water runs clear for fluffy, separated grains; let it rest covered for 5 minutes before fluffing.
• Keep it gluten-free: choose certified GF spices, stock, and condiments (Worcestershire, Dijon, hot sauce, and andouille).
• Dairy-free swap: use all avocado oil for brushing and searing the fish; skip the butter entirely.

Variations

• Pescatarian Dirty Rice: swap the andouille for 6–8 oz finely chopped cremini mushrooms; add 1/2 tsp smoked paprika for depth.
• Milder Spice: halve the cayenne in the blend and finish fish with a squeeze of lemon to brighten without heat.
• Thick Fillets: after searing both sides, finish in a 400°F oven for 3–5 minutes to reach 145°F without burning the crust.

Storage & Make-Ahead

Spice blend can be made up to 1 month ahead and stored airtight. Dirty rice keeps 3–4 days refrigerated; reheat with a splash of stock. Slaw can be dressed up to 1 day ahead; it will soften slightly but stay crisp. Blackened fish is best fresh; if needed, refrigerate up to 2 days and reheat gently in a 300°F oven for 8–10 minutes to preserve moisture (the crust will soften a bit).

Nutrition (per serving)

Approximate: 740 calories; 45 g protein; 34 g fat; 70 g carbohydrates; 5 g fiber; 1,050 mg sodium. Values will vary based on fish type, sausage brand, and salt level in stock.