Pat crab meat dry with paper towels to remove excess moisture. Combine chopped shrimp, scallions, garlic, parsley, cilantro (if using) and 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper in a bowl; gently toss to distribute.

Make batter

In a medium bowl whisk together flour, cornstarch and baking powder. In a separate small bowl whisk the egg, mayonnaise and Dijon until smooth. Stir wet mixture into dry ingredients, then slowly add cold sparkling water until you reach a thick, slightly loose batter (about 2/3 cup). Batter should be thick enough to hold crab and shrimp but still pourable. Adjust with up to 2 more tablespoons water if needed.

Combine batter with seafood

Fold the crab and shrimp mixture into the batter gently to avoid breaking up crab lumps. Taste a small dab of batter (cook a tiny spoonful in a skillet) and check seasoning; add up to 1/2 teaspoon additional salt if necessary.

Heat oil

Pour vegetable oil into a 10–12 inch skillet to a depth of about 1/4 inch and heat over medium-high until shimmering and a drop of batter sizzles and bubbles immediately (about 350°F).

Fry fritters

Using a 2-tablespoon scoop or spoon, gently spoon batter (about 2 tablespoons per fritter) into the hot oil, flatten slightly to a 3-inch round. Fry in batches without crowding, 2–3 minutes per side until deep golden brown and cooked through. Use a slotted spatula to flip once. Internal shrimp should be opaque and fritters should be crisp. Transfer to a paper towel–lined rack to drain; keep warm in a low oven (200°F) while finishing remaining batter.

Grilled corn salsa

If using fresh corn, grill the ears whole over a hot grill or char in a hot cast-iron skillet until slightly blackened in spots (about 8–10 minutes), turning occasionally. Let cool slightly, then slice kernels from the cob. If using thawed frozen corn, briefly cook in a hot skillet until charred in places (3–4 minutes).

Combine corn, cherry tomatoes, red bell pepper, red onion and cilantro in a bowl. Drizzle with olive oil and lime juice, season with 1/2 teaspoon salt and 1/4 teaspoon pepper, then toss gently. Taste and adjust acidity or seasoning. Keep at room temperature until serving.

Lobster ginger sauce

In a small bowl whisk together mayonnaise, yogurt (or crème fraîche), lemon juice, soy sauce, honey and toasted sesame oil until smooth.

Add grated ginger, minced shallot and chopped lobster meat; fold to combine. Season with 1/4 teaspoon kosher salt and a pinch of black pepper. Chill for at least 15 minutes to allow flavors to meld; stir before serving. Adjust consistency with 1–2 teaspoons water if too thick.

Assembly & serving

Place 1–2 warm fritters on each starter plate or a shared platter. Spoon about 1–2 tablespoons grilled corn salsa over or alongside each fritter.

Drizzle or dot 1 tablespoon lobster ginger sauce beside each fritter (or pass sauce in a small bowl). Garnish with microgreens or chopped parsley and a lemon wedge. Serve immediately while fritters are hot and crisp.