These crab cake burgers, made with plenty of crab, pimento, Old Bay seasoning, and a little egg, mayo, and crackers to bind, are an enduring summer classic.
In a medium bowl, combine the egg, mayonnaise, pimiento, 1/3 of the crumbled crackers, salt, Old Bay, and parsley and mix well.
Gently fold in the crabmeat. The mixture will be wet.
Using your hands, gently shape the mixture into 4 patties, being careful not to press them too compactly. Cover and refrigerate for up to 4 hours.
Gently coat the crab cakes with the remaining crumbled crackers, sprinkling some of the cracker crumbs over the crab cakes and then turning and repeating.
Preheat a skillet over medium-high heat. Add at least 2 tablespoons oil and heat until hot but not smoking.
Add 2 crab cakes to the skillet and cook until golden brown, 3 to 5 minutes per side, gently turning the crab cakes once with a thin metal spatula. Transfer to a plate. Repeat with the remaining crab cakes, adding more oil if needed.
Place a crab cake on each bun and top with a tomato slice, if using. Serve with tartar sauce on the side.