Slow-Roasted Barramundi with Lemon Myrtle Butter Sauce

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · ·

Delicately slow-roasted barramundi fillets accented with a fragrant lemon myrtle butter sauce for a tender, aromatic seafood dish. This australian-inspired seafood ready in about 40 minutes blends unsalted butter, finely chopped lemon myrtle leaves, minced garlic cloves into a versatile sauce that lifts everything from grain bowls and roasted vegetables to grilled proteins — a small-batch staple worth keeping in the fridge. Each serving lands at about 280 calories and feeds 4, so a small batch covers several meals across the week without taking over the fridge. 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

Instructions

  1. Step 1: Preheat oven to 275°F (135°C). Place 4 barramundi fillets on a lined baking tray and drizzle 2 tbsp olive oil evenly over them; sprinkle with 1 tsp sea salt and 1/2 tsp white pepper.
  2. Step 2: Roast the barramundi in the oven for 25-30 minutes until the fish flakes easily with a fork and is opaque.
  3. Step 3: While the fish roasts, melt 4 tbsp unsalted butter in a small saucepan over medium-low heat. Add 1 tbsp finely chopped lemon myrtle leaves and 2 minced garlic cloves, cooking gently for 3 minutes until fragrant but not browned.
  4. Step 4: Remove the butter from heat and stir in 1 tbsp fresh lemon juice and 2 tbsp chopped fresh parsley.
  5. Step 5: Serve the slow-roasted barramundi fillets drizzled generously with the warm lemon myrtle butter sauce.

Equipment for this recipe

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Frequently asked questions

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

Total time is about 40 minutes (10 min prep + 30 min cook). A small batch typically covers several meals in the week — store as the recipe directs.

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

Transfer to an airtight jar and refrigerate for up to 5–7 days. Most sauces freeze well for up to 2 months — portion into small containers or freezer bags so you can thaw only what you need. Stir before serving; cream- or yogurt-based sauces may separate on standing.

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

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 Butter Sauce 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 Butter Sauce?

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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