This sando is San Francisco on a plate. The in-season Dungeness crab plus good old sourdough makes this dish feel like home every time.
Technique tip: Make your crab cakes first so that you have plenty of time to let the patties chill while you caramelize the onions and make the aioli. Chilled crab cakes are much easier to handle and flip than freshly formed ones!
Swap option: Try rye bread instead of sourdough for more of a patty melt flavor. Take it over the top by sprinkling a few caraway seeds into your caramelized onions.
For the caramelized onions:
Cut the top and bottom off of the onion, then slice it in half lengthwise. Remove the skin and one half at a time, cut the onion into long slices.
Heat the oil in a medium skillet and add the sliced onion. Put a lid on it and lower the heat to medium-low. Cook for about 20-30 minutes, stirring every 5 minutes, until the onions are brown, sticky and fragrant. Set aside.
For the Old Bay aioli:
Whisk together all ingredients. Set aside.
For the Dungeness crab cakes:1.
Saute the celery and shallot in a little olive oil until the shallot is translucent and the celery has started to soften, about 5 minutes. Set aside to cool.2.
Whisk together the mayo, lemon juice, lemon zest, egg, Worcestershire and pimento.3.
In a medium bowl, combine the crab, mayo mixture, cooled celery/shallot mixture, 1/4 cup of panko and all of the herbs and spices. Fold gently to combine.4.
Divide the crab cake mixture into 4 portions. Form each portion into a patty directly onto a square of wax paper (make the patty the same size and shape as your sourdough slices).5.
Sprinkle 1 tablespoon of panko breadcrumbs on the top side of each patty. Chill the patties in the fridge while you get the aioli and onions ready.6.
Heat a large skillet over medium-high heat. Drop butter into the skillet and spread it around. Flip the crab cake patties panko-side down onto the hot buttered skillet and sprinkle the exposed side with the rest of the panko, 1 tablespoon per patty. Cook until brown, about 4 minutes. Using a large spatula, gently flip the crab cakes and cook for another 4-5 minutes. Transfer to a plate while you get the bread ready for sandwich assembly.
Spread about a tablespoon of aioli on 4 of the sourdough slices. Put a crab cake patty on top of the aioli and spread a little more aioli on top of each crab cake. Top that with a scoop of caramelized onion and a slice (or two!) of fontina. Top the sandwich with the remaining bread slices.
Heat a skillet on medium. Drop a couple tablespoons of butter and spread it around. Arrange the sandwiches in the skillet on top of the butter and while cooking, spread more softened butter on top of each sandwich. When browned on that side, flip the sandwiches and cook until browned and the cheese is melted. Serve immediately while warm and melty.