PURGE AND CLEAN THE RAZOR CLAMS (BEGIN AT LEAST 30 MINUTES AHEAD)
1. PURGE: Place live razor clams in a large bowl of cold salted water (2 tablespoons fine sea salt per quart of water). Leave in a cool place for 30 minutes to 2 hours. The clams will expel sand and grit.
2. RINSE: Lift clams from the soaking water — do not pour through them. Rinse each clam thoroughly under cold running water, scrubbing shells gently.
3. CHECK VIABILITY: Discard any clams with cracked shells or any that remain open and do not respond when tapped. Live clams will close or show movement.
4. Keep cleaned clams cold until ready to cook.

PICKLE THE FENNEL
5. PREPARE THE FENNEL: Trim the fennel bulb, removing the tough outer layer and core. Slice paper-thin using a mandoline or very sharp knife. Reserve any delicate fronds for garnish.
6. MAKE THE LIQUOR: In a small saucepan, combine cider vinegar, white wine, sugar, allspice berries, fennel seeds, star anise, peppercorns, and salt. Bring to a boil, stirring until sugar dissolves. Reduce heat and simmer for 2 minutes.
7. PICKLE: Place sliced fennel in a heatproof bowl and pour hot liquor over it. Cover and leave at room temperature for at least 15–20 minutes while preparing remaining components.

PREPARE THE JERUSALEM ARTICHOKES (TWO WAYS)
8. PEEL AND SLICE: Peel the artichokes and place immediately in water acidulated with lemon juice. Cut about two-thirds into ¼-inch (5 mm) discs for cooking in butter. Cut the remaining third into paper-thin slices on a mandoline for crisps.
9. PAR-COOK THE DISCS: Melt butter in a small saucepan over medium-low heat. Add artichoke discs with a pinch of salt. Cook gently for 8–10 minutes, turning occasionally, until just tender when pierced with a knife but still holding their shape. Set aside in the butter.
10. FRY THE CRISPS: Pat thin artichoke slices very dry with paper towels. Heat vegetable oil in a small deep saucepan to 325°F (160°C). Fry in small batches for 2–3 minutes until golden and crisp. Drain on paper towels and season immediately with fine sea salt.

STEAM THE RAZOR CLAMS
11. HEAT THE PAN: Place a large lidded sauté pan over high heat until very hot. Add the sliced shallot and let it sizzle for 15–20 seconds.
12. STEAM: Add white wine and immediately add the purged, rinsed razor clams. Cover tightly. Steam for 30–40 seconds only. Shells will open and meat will turn from translucent to opaque white. Remove from heat immediately.
13. REMOVE AND TRIM: Transfer clams to a plate with tongs. Remove meat from shells. Using a small sharp knife or kitchen scissors, trim away the dark stomach sac and mouth parts from each clam. Keep only the clean white and pale tan meat — the body and siphon. Rinse each trimmed clam briefly under cold water. Set aside on a warm plate, loosely covered.
14. RESERVE THE LIQUOR: Strain pan liquid through a fine-mesh sieve lined with damp muslin or paper towel. Reserve all of this clam-flavoured liquor for the beurre blanc.

MAKE THE BEURRE BLANC
15. MAKE THE REDUCTION: In a small saucepan, combine finely diced shallot, white wine, white wine vinegar, and all strained clam cooking liquor. Bring to a boil over medium heat, then reduce to a gentle simmer. Cook until reduced to about 2 tablespoons.
16. MOUNT WITH BUTTER: Reduce heat to lowest setting. Add cold butter one or two cubes at a time, whisking constantly. Each addition should be nearly incorporated before adding the next. The sauce should become creamy, pale, glossy, and velvety. If the pan gets too hot, lift it off the heat and keep whisking.
17. SEASON AND FINISH: Season with lemon juice, salt, and white pepper. Strain through a fine-mesh sieve if desired. Add par-cooked artichoke discs to the sauce to warm through and absorb the clam-butter richness.
18. Keep beurre blanc warm but not hot while plating.

PLATE AND SERVE
19. Spoon beurre blanc onto two warmed plates, allowing artichoke discs to settle naturally. Arrange trimmed razor clam meat on top. Lift pickled fennel slices from their liquor and drape around and over the clams. Scatter Jerusalem artichoke crisps on top for height and crunch. Finish with chervil or dill fronds and the lightest drizzle of olive oil.
20. Serve immediately — beurre blanc waits for nobody.