- Extra virgin olive oil (EVOO), for drizzling
- 1 large shallot, finely chopped
- 2 cloves garlic, finely chopped
- 1 1/2 pounds fresh tuna steak, coarsely chopped
- 2 teaspoons herbes de Provence (2/3 palmful)
- 1 teaspoon fennel pollen or ground fennel
- 1 1/2 teaspoons celery seed (half a palmful)
- Salt and pepper
- 4 slices Gruyère cheese or 1 cup packed shredded Gruyère cheese
- Celery leaves
- Flat leaf parsley leaves
- A small handful of torn basil leaves or tarragon leaves
- 1/2-inch-thick slices of ripe tomato
- 1/2 cup Dijon mustard or Dijonnaise
- 2 tablespoons nonpareil capers or chopped capers
- Sliced or chopped cornichons
- Brioche buns, split
In a small skillet over medium heat, sauté the shallot and garlic in a little EVOO to soften. Cool completely.
Place the tuna in a food processor and pulse into coarse ground meat. Place the tuna in a bowl and add the shallot and garlic, herbes de Provence, fennel pollen, celery seed, salt and pepper. Form four patties and reheat the skillet over medium-high heat with a drizzle of EVOO. Add the tuna burgers to the pan and cook for 3 minutes on each side for pink centers and 5-6 minutes to cook through. Top the patties with cheese after they are flipped; loosely tent the pan with foil to melt cheese.
Combine the Dijon or Dijonaise with capers in a small bowl.
Place cheeseburgers on the bun bottoms and top with a mixture of celery, parsley and basil or tarragon leaves, sliced cornichons and tomatoes. Slather the bun tops with Dijon or Dijonnaise. Set the bun tops in place and serve.