Fresh tuna burger with caramelised onion and salad

Ingredients

For 1 serving

• Fresh tuna150 g
• Hamburger bun1
• Red onion80 g
• Balsamic vinegar1 teaspoon
• Lettuce30 g
• Tomatoes80 g
• Mustard1 teaspoon
• Extra virgin olive oil8 g
• Saltto taste
• Black pepperto taste

Contains: gluten, fish, mustard, sulphites,

Method

1. Peel and thinly slice the red onion. In a frying pan heat half the oil over low heat and stew the onion with a pinch of salt for 10 minutes, until soft and golden; add the balsamic vinegar and cook for 1 minute, until glossy.
2. Meanwhile chop the tuna by knife into roughly half-centimetre pieces, season with the mustard, salt and pepper and shape a firm burger about 2 cm thick.
3. Wash the lettuce and tomatoes and slice the tomatoes.
4. Split the burger bun and toast it in a pan or toaster for 1–2 minutes, until crisp.
5. Heat the remaining oil in a non-stick pan over high heat and cook the burger for 2 minutes per side, until browned outside and pink inside.
6. Build the bun with lettuce, tomato, the burger and the caramelised onion.