Preheat the oven to 400 degrees F.

Heat a large skillet over medium heat. Add 4 tablespoons of the butter and once it’s melted, stir in the onion with a pinch of salt. Cook, stirring often, until the onions soften. Stir in the flour to create a roux, stirring until the mixture is fragrant and golden.

Whisk in the mustard, Worcestershire sauce, 1 teaspoon salt and freshly cracked black pepper. With the mixture still over medium heat, whisk in the stock about ¼ cup at a time, until it’s thickened. Be sure to keep stirring so it doesn’t get lumpy! Once it’s thickened (this takes about 3 to 5 minutes), turn off the heat.

Place the egg yolks in a large bowl. Temper the yolks by adding a few spoonfuls of the warm flour/stock mixture, whisk immediately as you add it so it doesn’t cook the eggs. Do this until all of the stock has been add to the egg yolks. Stir in the crabmeat and parsley. Transfer it to a baking dish or small (oven safskillet for serving.

Heat the remaining 2 tablespoons butter in a skillet over medium heat. Once melted, add in the breadcrumbs and stir to coat, then toast for 3 to 4 minutes until they are golden and fragrant. Stir in the garlic. Sprinkle the bread crumbs over the crab dip.