Slow-Roasted Barramundi with Lemon Myrtle and Garlic Butter

By , Test Kitchen Director · Reviewed by AislePrompt Editorial · ·

Delicately slow-roasted barramundi fillets infused with lemon myrtle and topped with a fragrant garlic butter sauce. This australian-inspired seafood ready in about 40 minutes pairs lemon myrtle powder, unsalted butter, minced garlic cloves for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 280 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 10 min Cook: 30 min Serves 4 Australian cuisine 280 cal/serving
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Ingredients

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Instructions

  1. Step 1: Preheat oven to 275°F (135°C). Place 4 barramundi fillets skin-side down on a lined baking tray and drizzle with 2 tbsp olive oil.
  2. Step 2: Sprinkle 1 tsp lemon myrtle powder, 1 tsp sea salt, and 1/2 tsp freshly ground black pepper evenly over the fillets.
  3. Step 3: Roast the fillets in the oven for 25-30 minutes until the flesh is opaque and flakes easily with a fork.
  4. Step 4: Meanwhile, melt 4 tbsp unsalted butter in a small saucepan over low heat. Add 4 minced garlic cloves and cook gently for 2 minutes until fragrant but not browned.
  5. Step 5: Remove from heat and stir in 2 tbsp fresh lemon juice and 2 tbsp chopped fresh dill.
  6. Step 6: Once the barramundi is cooked, spoon the garlic butter sauce generously over each fillet and serve immediately with steamed greens or rice.

Frequently asked questions

How long does Slow-Roasted Barramundi with Lemon Myrtle and Garlic Butter take to make?

Total time is about 40 minutes (10 min prep + 30 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Slow-Roasted Barramundi with Lemon Myrtle and Garlic Butter?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep lemon myrtle powder from drying out.

Can I substitute ingredients in Slow-Roasted Barramundi with Lemon Myrtle and Garlic Butter?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Slow-Roasted Barramundi with Lemon Myrtle and Garlic Butter for a different number of people?

The recipe is written for 4 servings. Multiply each ingredient by (your serving target / 4). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

What goes well with Slow-Roasted Barramundi with Lemon Myrtle and Garlic Butter?

Australian seafood like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.

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