A recipe from the Good Food collection.
2 egg yolks, at room temperature
2 teaspoons dijon mustard
1 tablespoon tarragon vinegar, or to taste
200 ml (7 fl oz) olive oil
1 tablespoon finely chopped tarragon
750 g (1 lb 10 oz) minced (ground) beef
80 g (2¾ oz/1 cup) fresh white breadcrumbs
½ teaspoon finely grated lemon zest
5 drops of Tabasco sauce
1 egg, lightly beaten
olive oil, for brushing
6 good-quality hamburger buns
finely shredded lettuce, to serve
1. To make the tarragon mayonnaise, put the egg yolks, mustard and vinegar in a bowl and whisk together well. Whisking constantly, add the olive oil, a little at a time, making sure it is emulsified before adding more oil. Whisk until thick and creamy. Season to taste with sea salt and freshly ground black pepper, adding a little more vinegar if needed, then stir in the tarragon. Cover the surface of the mayonnaise directly with plastic wrap to prevent a skin forming.
2. To make the burgers, put the beef, breadcrumbs, lemon zest, Tabasco and egg in a large bowl and mix together well. Divide into six equal portions, then shape into patties 1.5 cm (⅝ inch) thick. With your thumb, make a cavity in the top of each burger. Place an oyster in the cavity and smooth the meat over to enclose the oyster completely. Refrigerate until required.
3. Heat a frying pan and brush lightly with olive oil. Cook the burgers on medium–high heat for 8 minutes on each side, turning only once.
4. Meanwhile, split the hamburger buns and lightly toast them, cut side up, under a hot grill (broiler). Keep warm.
5. Serve the burgers on the toasted buns with shredded lettuce and the tarragon mayonnaise.