The day before, prepare the apple pickles. Cut the apple into sapicon (2 mm cubes) and set aside. In a saucepan, bring the vinegar, water, a few grains of black Kampot pepper, the garlic, bay leaf, a pinch of sugar, and a pinch of salt to a boil. Once boiling, pour over the diced apples and place immediately in the refrigerator.
The next day, bring the bisque to a boil and cook for 5 minutes over medium heat. Add the heavy cream and cook for another 5 minutes. Off the heat, use an immersion blender or stand blender to blend the langoustine cream with the cold butter.
Remove the skin from the white puddings and cut them on the bias (15 mm thick).
In a frying pan with a drizzle of grape seed oil, sear each side of the white puddings. Deglaze with the licorice liqueur, mix, and remove from the pan.
In a small shallow bowl, pour a ladle of langoustine cream. Add 3 slices of white pudding, two small spoonfuls of apple pickles, and a few sprigs of chervil.