BBQ Barramundi Burger Grilled Cos

The first time I made these burgers, I was hosting a summer barbecue and my vegetarian neighbour actually asked for seconds. Theres something magical about how the smoky grilled lettuce transforms a fish burger from ordinary into absolutely extraordinary. My husband still talks about that tartare sauce with the grilled lemons.

Last summer I served these at a beach picnic and watched four skeptical burger lovers completely change their minds about fish sandwiches. The brioche buns soak up just enough of that tartare sauce while staying sturdy enough to handle the flaky barramundi. Now theyre the most requested dinner whenever we have friends over.

Ingredients

• 4 barramundi fillets (skinless): This Australian fish holds its shape beautifully on the grill and has a mild sweetness that pairs perfectly with the smoky elements
• 2 tbsp olive oil plus extra: Use a good quality one here since it forms the base of your marinade helps achieve those gorgeous grill marks
• 1 lemon (zest and halved): Both the fresh zest in the marinade and grilling the whole halves creates layers of bright citrus flavour
• 1 garlic clove: Minced finely so it distributes evenly through the marinade without overpowering the delicate fish
• 1 tsp sea salt and ½ tsp black pepper: Dont be shy with seasoning fish needs proper salt to really sing on the grill
• 4 brioche or burger buns: Brioche adds just enough sweetness to balance the tangy tartare but any sturdy bun works here
• 1 large head cos lettuce: Grilling romaine transforms it into something entirely different sweet smoky and still beautifully crisp
• 2 jalapeños: Grilling tames their heat while adding a lovely charred flavour that makes the tartare sauce unforgettable
• ½ cup mayonnaise: Use your favourite good quality brand since its the foundation of the sauce
• 2 tbsp capers: These little briny buds add pops of saltiness that complement the fish perfectly
• 1 tbsp each fresh dill and parsley: The combination brings freshness and colour that cuts through the rich elements
• 1 small shallot: Milder than onion and adds a subtle sweetness that balances the acidic components
• 1 tsp Dijon mustard: Just enough to give the tartare sauce depth and that classic creamy backbone
• 8 thin slices ripe tomato: Look for tomatoes that give slightly when pressed they should smell like summer sunshine
• 8 thin cucumber slices: Optional but I love how they add a cool crisp element against the warm fish

Instructions

Fire up the grill:

Get your BBQ or grill pan to medium high heat so its nice and hot when everything is ready to go

Marinate the fish:

Mix olive oil lemon zest garlic salt and pepper in a shallow dish then add barramundi fillets turning to coat. Let them sit for 10 minutes while you prep everything else

Prep the lettuce:

Separate your cos into large leaves and brush them lightly with olive oil they will grill up beautifully

Grill your citrus and chilies:

Place lemon halves cut side down and jalapeños on the grill. Let them go for 3 to 4 minutes until they are nicely charred and softened. Cool slightly then finely chop those jalapeños and squeeze the juice from the lemons

Make that magic tartare:

Combine mayonnaise grilled jalapeños 2 tablespoons of that precious grilled lemon juice capers dill parsley shallot Dijon mustard and salt and pepper. Pop it in the fridge to chill while you grill the rest

Cook the barramundi:

Grill those marinated fillets for 3 to 4 minutes per side. You want them just cooked through with gorgeous light char marks

Get smoky with the lettuce:

Throw your cos leaves on the grill for 1 to 2 minutes per side. They should be slightly wilted with gorgeous grill lines and that incredible smoky aroma

Toast your buns:

A quick toast on the grill adds structure and just enough crunch to hold everything together

Build your masterpiece:

Spread that tartare sauce generously on both bun halves then layer up grilled cos barramundi tomato and cucumber. Top with the bun and serve immediately while everything is still warm

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These burgers have become our go to when we want something that feels fancy but comes together in under an hour. Watching friends take that first bite their eyes widening at how good a fish burger can be has become one of my favourite kitchen moments.

Making It Your Own

Swap barramundi for snapper cod or any firm white fish you love. I have even used salmon when I wanted something richer and it worked beautifully. The key is choosing something that will hold up on the grill without falling apart.

Heat Level Hacks

Keep those jalapeño seeds in if you really want to feel the heat or add a dash of your favourite hot sauce to the tartare. My sister who loves spice adds sliced fresh jalapeño right on top of her burger. Serve with a crisp Australian Sauvignon Blanc or a cold pale ale to help balance those bold flavours.

Side Pairings

I love serving these with a simple potato salad or some grilled corn on the cob. A fresh green salad with a vinaigrette cuts through the richness nicely too.

• Keep extra napkins handy because these can get gloriously messy
• Have your fishmonger remove the skin if you prefer it that way
• Make double the tartare sauce because you will want to put it on everything

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There is something so satisfying about a burger that feels indulgent but is actually full of fresh vibrant flavours. Hope these bring a little sunshine to your table.

Recipe FAQ

→ What fish works best for this burger?

Barramundi is ideal for its firm texture and mild flavor that holds up beautifully on the grill. You can substitute with snapper, cod, or any firm white fish fillet that won't fall apart during cooking.

→ How spicy is the jalapeño tartare?

The tartare has mild to medium heat depending on the jalapeños. Grilling tames their intensity while adding smoky depth. For extra spice, leave some seeds in or add hot sauce to the mixture.

→ Can I cook this indoors?

A grill pan works perfectly for stovetop preparation. You'll still get great char marks and flavor, though outdoor BBQ adds extra smokiness to both fish and lettuce leaves.

→ What makes grilled lettuce special?

Grilling cos lettuce creates a wonderful smoky flavor and slight wilt while maintaining crunch. It takes just 1-2 minutes per side and adds incredible depth to the burger texture.

→ How long does the tartare keep?

The grilled lemon jalapeño tartare will stay fresh in the refrigerator for up to 3 days. The flavors actually develop and meld better overnight, making it great to prep ahead.

→ What drinks pair well?

A crisp Australian Sauvignon Blanc cuts through the rich tartare beautifully, while a pale ale complements the grilled fish. For non-alcoholic options, try sparkling water with lime.