Dice the carrots, leeks and onion. Add to a pot with lemon juice, white wine and water. Bring all ingredients to a boil.
Poach the lobster tails in the court bouillon for 5 minutes and the claws for 6. When cooked, remove the flesh carefully from the shell and set aside. Discard bouillon or store for later use.
Combine egg yolks, mustard, ketchup and lemon juice in a medium bowl – slowly whisk in the canola oil and continue until thick.
Soft boil the potatoes and season with salt, pepper and lemon juice. Build the salad on a plate and garnish with the soft herbs and cornichons.
Chef’s Tip: If you’re planning to make this dish a second time, the bouillon will keep for two days in the fridge and can be used twice.