How to Make It
Combine all of the ingredients in a bowl.
Light a grill. Brush the grate with oil. Melt the butter in a saucepan. Add the garlic, shallots and seafood seasoning and cook over high heat until fragrant, about 2 minutes; don't let the garlic brown.
Grill the rolls until golden; move the rolls to a cooler part of the grill. Brush the crabs generously with the aromatic butter and season with salt and pepper. Grill the crabs over high heat, turning occasionally, until bright red, crisp and charred in spots, about 4 minutes. Spread the tartar sauce on the rolls, top with the crabs and serve.