18 mini potato buns
1/2 cup plus 2 tablespoons mayonnaise
2 tablespoons unsalted butter, melted, plus more for brushing
1 large egg
1 teaspoon Old Bay Seasoning
1 teaspoon Worcestershire sauce
1 teaspoon yellow mustard
Kosher salt
1 pound lump crabmeat, picked through
10 strips bacon
Finely grated zest of 1 lemon
Freshly ground pepper
Diced red onion, sliced tomatoes and lettuce leaves, for topping
Pickles, for serving (optional)