Salmon Burgers with Lemon-Caper Aioli and Kale Slaw

Salmon Burgers:

1 pound skinless salmon, cut into cubes

1/2 cup fresh flat-leaf parsley leaves 

1 teaspoon onion powder 

1 teaspoon kosher salt 

1/2 teaspoon garlic powder 

1/4 teaspoon freshly ground black pepper 

10 fresh basil leaves 

1 large egg 

Zest of 1 lemon 

2 tablespoons canola oil 

Butter, for buttering the buns

4 potato buns, split

Sliced Roma tomatoes, for serving

Watercress, for serving

Lemon-Caper Aioli:

1/2 cup mayonnaise

2 teaspoons capers, chopped 

1 teaspoon chopped fresh basil 

1 teaspoon chopped fresh parsley 

1 clove garlic, grated 

Juice of 1 lemon 

Kale Slaw:

1/2 cup mayonnaise

1/2 cup plain Greek yogurt 

2 tablespoons Dijon mustard 

2 tablespoons apple cider vinegar 

1 teaspoon honey 

1/2 teaspoon celery seeds 

1/2 teaspoon kosher salt 

1/4 teaspoon freshly ground black pepper 

5 cups shredded kale

3 cups shredded cabbage 

3 cups shredded carrots 

1 cup sunflower seeds