How to Make It
Preheat the broiler. In a medium bowl, combine the bread crumbs with 1 1/2 tablespoons of the mustard, the parsley, butter, shallot and crushed red pepper. Season lightly with salt.
In a medium, shallow baking dish, whisk the heavy cream with the remaining 1 tablespoon of mustard.
Arrange the sardines in the baking dish, skin side down. Scatter the bread-crumb mixture on top. Broil the sardines 6 inches from the heat for 1 minute and 30 seconds, or until heated through and golden brown. Serve at once.