Ingredients

For the dip
1 tablespoon unsalted butter
1 large shallot, minced
1/2 cup (4 ounces) cream cheese, at room temperature
1/4 cup heavy (whipping) cream
3 tablespoons mayonnaise
1 tablespoon Dijon mustard
1 tablespoon fresh lemon juice
1/3 cup thinly sliced green onions, including green tops
1 1/2 tablespoons minced fresh flat-leaf parsley
3/4 teaspoon salt
3/4 teaspoon Old Bay Seasoning
1 pound fresh lump crabmeat, picked over for shells and well drained
For the topping
3 tablespoons unsalted butter
2/3 cup panko (Japanese bread crumbs) or other unseasoned bread crumbs
1 1/2 teaspoons freshly grated lemon zest
pinch of salt
crostini, for serving

Directions

1. In a medium skillet, melt the butter over medium heat. Add the shallot and saute for about 2 minutes until soft but not browned. Remove from the heat.
2. Add the cream cheese, cream, mayonnaise, mustard, and lemon juice. Using a rubber spatula, stir to combine, then fold in the green onions, parsley, salt, and Old Bay. Fold in the crabmeat, breaking up any large chunks with a fork. Transfer the crab dip to a shallow baking dish. Set aside.
3. Position a rack in the upper third of the oven and preheat to 425°F.
4. To make the topping, in a small skillet, melt the butter over medium heat. Add the panko and toast, stirring constantly, for about 2 minutes until the crumbs are golden brown and crisp.
5. Remove from the heat and stir in the lemon zest and salt. Scatter the topping evenly over the crab dip.
6. Bake until heated through and bubbly at the edges and the topping is golden, 12-15 minutes. Serve warm with the crostini.

Serves 8.

Do ahead: The crab dip, without the panko topping, can be prepared 1 day in advance. Cover and refrigerate. Remove from the refrigerator 1 hour before baking. The panko topping can be prepared up to 1 day in advance. Transfer to an airtight container and store at room temperature. Scatter the topping over the crab just before baking.