For sauce, mince capers and parsley and whisk together with other ingredients. Feel free to taste and adjust seasoning to your liking.
To start burgers, peel shrimp and devein with a paring knife or buy peeled and cleaned shrimp. Take about half of the shrimp and roughly chop it and set aside. This will be the texture in the burgers later.
In a food processor, pulse the piece of bread until it is in tiny pieces. Then add the rest of the shrimp, the egg white, the onion, the parsley and the spices and pulse a few times until it’s in a rough paste.
Transfer shrimp paste to a bowl and fold in chopped shrimp. If the mixture is really wet, add breadcrumbs. You may or may not need them.
When mixture is formable, but still pretty wet, divide it into three even balls. You can either cook these immediately or store them in the fridge for later.
When you want to cook a burger, add a drizzle of neutral oil to a skillet over medium heat. Once the oil is shimmering hot, add a burger ball and press it down a bit to form a patty in the pan.
Let the burgers cook for about 4-5 minutes per side.
Once burgers are cooked through completely, serve them on a toasted bun with a smear of tartar sauce and veggies on the side.