• 2 Tbsp. butter
• 1 leek , white and light green parts only, finely chopped
• 1 rib celery , finely chopped
• 1 small yellow onion , finely chopped
• 1 pound lump crabmeat , preferably Dungeness, picked through to remove any bits of shell
• 1/2 cup mayonnaise
• 1/2 cup chopped flat-leaf parsley
• 1/8 tsp. cayenne pepper
• 1 1/2 tsp. kosher salt
• 1/4 tsp. freshly ground black pepper
• 2 1/2 cups fine dried bread crumbs , divided
• 1/2 cup all-purpose flour
• 3 eggs , lightly beaten
• 1/2 cup canola oil

• 1/2 cup mayonnaise
• 1 1/2 Tbsp. lemon juice (from about 1/4 lemon)
• 1 Tbsp. chili sauce , such as Sriracha
• 1/4 tsp. kosher salt
• 1/8 tsp. freshly ground black pepper

• 2 Tbsp. butter
• 12 (3-inch) slider rolls or soft dinner rolls , split
• 3 cups shredded iceberg lettuce (from about 1/2 head)

To make crab cakes: Heat butter in a large skillet over medium heat. Add leek, celery, and onion, and cook, stirring often, until soft and golden, about 10 minutes; set aside to cool.

In a large bowl, gently fold together crab, mayonnaise, parsley, cayenne, salt, pepper, and onion mixture. Add 1 cup bread crumbs and stir just until combined. Shape crab mixture into 12 (3-inch) patties, using about 1/3 cup of the mixture for each. Transfer to a sheet tray.

Put flour, eggs, and remaining 1 1/2 cups bread crumbs into 3 separate wide, shallow dishes. Working with 1 patty at a time, dredge in flour, then egg, then bread crumbs, shaking off excess each time. Dredge once more in egg, then bread crumbs.

Heat oil in a large, deep skillet over medium heat until very hot but not smoking, about 2 minutes. Arrange 6 patties in skillet and cook, flipping once, until deep golden brown and hot throughout, 6 to 8 minutes. Transfer to a paper-towel-lined plate and set aside. Repeat with remaining patties.

To make spicy mayo: In a small bowl, stir together all ingredients until combined.

Meanwhile, working in 2 batches, melt 1 tablespoon butter in a large skillet over medium-high heat. Brown cut sides of 6 rolls until toasted and golden, 1 to 2 minutes; transfer to a plate and repeat with remaining butter and rolls.

Spread a bit of spicy mayo, to taste, on each bun, then top with lettuce and crab cakes. Serve immediately.