Make the langoustine broth

• Toast the reserved langoustine shells and heads in a saucepan.
• Cover with water and simmer to extract all the flavour.
• Strain the broth and reduce it, then stir in the milk to infuse it.

Prepare the brioche dough

• Mix the flour, sugar, crumbled yeast and the infused milk in a bowl.
• Add the eggs one at a time, then the salt.
• Knead in the softened butter until the dough is smooth and elastic.
• Cover and let the dough rise until doubled in size.

Cook the langoustines

• Heat the olive oil in a frying pan.
• Sear the shelled langoustines briefly until just cooked.
• Season and set aside.

Mix the filling

• Combine the mayonnaise with the lemon zest and juice.
• Fold in the chopped chives and the cooked langoustines.

Bake the brioche waffles

• Heat the waffle maker and brush it with butter.
• Divide the risen dough into portions and bake until golden and crisp.

Assemble the sandwich

• Fill the warm brioche waffles with the langoustine mixture.
• Serve immediately.