Quickly rinse the crayfish and pat them dry.

In a heavy-bottomed skillet, pour the olive oil, sprinkle with Herbes de Provence and Espelette pepper to taste, add the crayfish, and gently mix them with the flavored oil. Sauté for a few minutes over fairly high heat until the crayfish take on a light color.

Set aside about 1/4 for decoration.

In a blender, quickly blend the remaining crayfish with 2 tablespoons of heavy cream and a few drops of lemon juice, leaving small pieces.

In a mixing bowl with a whisk attachment, whip the remaining heavy cream with the mascarpone, adding salt and pepper to taste.

Add the crayfish cream, sprinkle with Herbes de Provence and Espelette pepper, and mix gently.

Spoon the mousse into the verrines of your choice and arrange the reserved crayfish decoratively on top, sprinkling with Herbes de Provence.

Cover with plastic wrap and refrigerate until ready to serve.