Preparation Put oven rack in middle position and preheat oven to 425°F. Cook scallion, bell pepper, and garlic in 2 tablespoons butter in a 1-quart heavy saucepan over moderate heat, stirring, 1 minute, then whisk in flour and cook roux, stirring constantly, 1 minute. Add cream and bring to a boil, whisking. Reduce heat and simmer, whisking, 2 minutes. (Mixture will be thick.) Remove from heat and whisk 1 minute, then whisk in yolk, basil, mustard, chile sauce, lemon juice, and salt and chill, uncovered, until cooled, about 15 minutes. While sauce is cooling, line a tray with wax paper and butter a shallow baking pan. Pulse bread, chives, parsley, and pepper in a food processor until finely chopped and transfer mixture to a plate. Stir crabmeat into sauce and form into 12 (3-inch) patties, arranging them on tray. Gently coat each crab cake with crumb mixture and place in baking pan. Drizzle with remaining melted butter and bake until golden and hot, 8 to 10 minutes.
Preparation Put oven rack in middle position and preheat oven to 425°F. Cook scallion, bell pepper, and garlic in 2 tablespoons butter in a 1-quart heavy saucepan over moderate heat, stirring, 1 minute, then whisk in flour and cook roux, stirring constantly, 1 minute. Add cream and bring to a boil, whisking. Reduce heat and simmer, whisking, 2 minutes. (Mixture will be thick.) Remove from heat and whisk 1 minute, then whisk in yolk, basil, mustard, chile sauce, lemon juice, and salt and chill, uncovered, until cooled, about 15 minutes. While sauce is cooling, line a tray with wax paper and butter a shallow baking pan. Pulse bread, chives, parsley, and pepper in a food processor until finely chopped and transfer mixture to a plate. Stir crabmeat into sauce and form into 12 (3-inch) patties, arranging them on tray. Gently coat each crab cake with crumb mixture and place in baking pan. Drizzle with remaining melted butter and bake until golden and hot, 8 to 10 minutes.