Rinse stalks under cold running water and scrub the ridges clean. Trim the base and any discolored ends. Slice on a bias or into uniform pieces for even cooking — thin slices for fast sautés, half-inch pieces for longer covered cooking. Use inner stalks if working with conventional celery; they are less fibrous. Have all aromatics prepped before the pan goes on.

Set a large Skillet over medium heat for softer results or medium-high for a quicker, crunchier sauté. Add butter or oil and heat until shimmering or foamy before adding celery. Do not crowd the pan or the celery will steam instead of sauté. Add celery to the hot fat. If cooking with onion, add it first and cook about 5 minutes until translucent, then add celery. Add garlic or scallions after the celery has cooked 1 minute, then cook 30 seconds more. Stir occasionally to allow some color to develop. For tender-crisp celery, cook 2 to 3 minutes over medium-high heat. For softer celery, cook 5 to 10 minutes over medium heat. To go fully tender, add a splash of water, cover, and cook an additional 5 minutes. Total time is roughly 6 to 10 minutes depending on thickness and desired texture.

In a large Mixing Bowl, whisk together the ⅓ cup mayonnaise good quality, such as Hellmann's, fresh 1 tbsp fresh lemon juice plus zest of half a lemon, 1 tbsp fresh lemon juice plus zest of half a lemon zest, 1 tsp Dijon mustard (if using), 3 tbsp unsalted butter softened, for toasting buns, and freshly ground ¼ tsp black pepper freshly ground. Fold in the diced 2 stalks celery finely diced and 2 tbsp fresh chives finely chopped. Add the 2 lb cooked lobster meat from about 4 whole lobsters or 4 lobster tails, cut into 1-inch chunks chunks and gently toss until everything is evenly coated. Taste and adjust seasoning. Cover and refrigerate for at least 10 minutes to let the flavors meld.

Rinse stalks under cold running water and scrub the ridges clean. Trim the base and any discolored ends. Slice on a bias or into uniform pieces for even cooking — thin slices for fast sautés, half-inch pieces for longer covered cooking. Use inner stalks if working with conventional celery; they are less fibrous. Have all aromatics prepped before the pan goes on.