Grilled Tuna Steaks with Lemon Caper Butter and Autumn Mash

Grilled Tuna Steaks with Lemon Caper Butter and Autumn Mash served on a blue plate
  • 4 servings
  • 25 minutes to prepare
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  • 2 sweet potatoes, peeled and diced
  • 2 carrots, peeled and diced
  • 100g butter, softened
  • 25g capers, chopped
  • 1 lemon, zest only
  • 1tbsp cumin seeds
  • 25g butter
  • 75g kale, shredded
  • Drizzle oil
  • 4 tuna steaks
  • Salt and pepper


Sometimes simple suppers are the best, and this grilled tuna dish with its classic flavours is one of those. If you don’t have time to make your own flavoured butter, why not ask at the fishmonger counter in store for one of our ready made ones?


  1. Bring a pan of salted water to the boil, add the diced sweet potato and carrot. Cook for 15 minutes or until tender. Drain and set to one side.
  2. Place the 100g softened butter, capers and lemon zest into a bowl, season with salt and pepper and mix well. Spoon onto a square of parchment paper and wrap to form a cylinder shape. Twist the ends and place into the fridge to chill.
  3. Heat a frying pan over a medium heat, add the cumin seeds and dry fry for 3 minutes or until they become fragrant.
  4. Add the 25g butter to the frying pan to melt. Add the kale to the pan and sauté for 5 minutes.
  5. Add the cooked sweet potato and carrot, mash with a fork and season to taste.
  6. To cook the tuna, heat a griddle pan over a high heat. Brush each tuna steak with a little olive oil and cook for 1 minute on each side.
  7. Top each tuna steak with a slice of lemon caper butter and serve with a dollop of autumn mash.

Chefs Tip

This butter is delicious with white fish, salmon and even on steaks. Make a double batch, wrap in parchment paper and freeze for up to 3 months. To cook the perfect tuna steak, use a non-stick griddle pan, oil the fish not the griddle, and heat the pan to smoking hot. Grill for 1 minute on each side to ensure the centre stays pink.

Wine Match – Louis Jadot Macon Villages Blanc

Fresh, clean and fruity with subtle green apple and pear flavours and a touch of creaminess on the palate means that this white wine works exceptionally well with our simple Tuna Steak and Caper Butter Sauce recipe. Find it in the French white wine section.