Inspect the lump crab meat for shells and gently pick through to remove any stray pieces. Place crab in a large mixing bowl. Finely chop the parsley and slice the green onions thinly; add both to the bowl.

Combine binder

In a smaller bowl whisk together 1/2 cup mayonnaise, the egg, Dijon mustard, Worcestershire, 1 tablespoon lemon juice, Old Bay, kosher salt, and black pepper until smooth and homogenous.

Mix gently

Pour the binder over the crab and add 3/4 cup panko. Using a rubber spatula or your hands, gently fold the mixture just until combined — avoid breaking up the lumps of crab. If the mixture feels too loose to form, add up to 2 tablespoons more panko.

Portion and coat

Divide the mixture into 8 equal portions (about 2 ounces / 56 g each) for small cakes or 4 portions for larger cakes. Shape each portion into a compact patty about 3/4-inch thick. Lightly press each patty into the extra 1/2 cup panko to coat exterior; shake off excess.

Chill

Place formed crab cakes on a parchment-lined tray and refrigerate, uncovered or lightly covered, for at least 30 minutes and up to 2 hours — this helps them hold together during cooking.

Cooking

Heat a large skillet over medium heat. Add 2 tablespoons butter and 2 tablespoons oil; swirl to coat. When fat is shimmering and butter foaming but not burning, add crab cakes (work in batches so they are not crowded).

Cook without moving for 3–4 minutes, until the underside is deep golden brown. Carefully flip using a wide spatula and cook the second side 3–4 minutes until golden and heated through. If cakes are thick, reduce heat to medium-low and cover loosely for 1–2 minutes to ensure cooked center without overbrowning.

Transfer cooked crab cakes to a wire rack or paper towel-lined plate to drain briefly. Keep warm on low oven (200°F / 95°C) if cooking in batches.

Optional Lemon Aioli

Whisk together 1/2 cup mayonnaise, lemon zest, 1 tablespoon lemon juice, minced garlic, hot sauce (if using), 1/8 teaspoon salt and a pinch of black pepper until smooth. Adjust seasoning to taste and chill until ready to serve.

Serve a dollop alongside warm crab cakes and garnish with additional lemon wedges and chopped parsley if desired.