Cut 2 pounds (900 g) of the salmon into strips and place in the freezer until stiff, about 20 minutes. Roughly chop the remaining 1/2 pound (225 g) of salmon. Remove the salmon from the freezer and grind, using the coarse or medium grind plate.If you do not have a grinder, place in the bowl of a food processor fitted with the chopping blade and pulse until coarsely ground.

In a large bowl, combine the ground and chopped salmon with soy sauce, mustard, garlic, parsley, egg, and bread crumbs.

Using your hands, shape the salmon into 6 patties, about 1/2-inch (1 cm) thick. Season with salt. Heat a skillet over high heat until very hot. If you have an infrared thermometer, the skillet should register at least 500°F (250°C). Or test by brushing on a bit of oil.

When the skillet starts to smoke, it is ready. Brush the skillet with vegetable oil. Place the patties on the skillet without overcrowding. (You may have to do this in batches.)

Cook for 3 minutes. Turn the patties over and cook on the other side for 2 minutes until the exterior is crispy and the burgers register an internal temperature of 135°F (57°C). Transfer the patties to a platter, squeeze with lemon, and tent loosely with foil. While the patties are resting, toast the buns.

To serve: Spread Dill Mayonnaise on the the bottom halves of the buns and place the burgers on top. Add a dollop of creme fraiche, a sprinkle of chives, 2 teaspoons (11 g) of Dilled Salmon Roe (if using), and a few leaves of arugula. Place the remaining halves of buns on top.