Cook the langoustines in court-bouillon or salted boiling water for 3 minutes. Drain and shell them, reserving the tails.
Preheat the oven to 200°C (thermostat 6). Place the red pepper on a baking sheet and roast until charred. Remove, rinse under cold water, and rub off the skin. Pat dry, halve lengthwise, remove seeds, and cut into strips. Wash the zucchini and slice thinly with a sharp knife.
Heat olive oil in a sauté pan over high heat. Season the langoustine tails with salt and pepper, then sear in the hot oil for 1 minute per side. Remove with a slotted spoon and keep warm.
In the same oil, sauté the zucchini slices and red pepper strips. Deglaze with pastis, crumble in the savory, and reduce until nearly dry. Add the fish stock and simmer.
Remove the vegetables, pat dry on paper towels, and set aside. Continue reducing the sauce. Arrange zucchini slices in a circle on warmed plates (6 per person), topping each with a langoustine tail. Place pepper strips in the center and keep warm.
Finish the sauce with ground pepper, whisk in the butter gradually, and season to taste with salt. Pour over the plates to serve.
