Whip the butter with a whisk. Rinse and finely chop the rocket.
Then mix these two ingredients together.
Cut the pickles in half lengthwise.
Cut the baguette in half, slice each half open and spread some of the rocket butter on them. Place slices of the sausage, Comté cheese and pickles on them, then close.
The butter may be whipped with an electric mixer for easier handling.