Curried Chicken Sandwich | Food Stuff

Ingredients

• 1/2 quart buttermilk
• 4 stalks celery, thinly sliced
• 3/4 teaspoon celery seeds
• 2 teaspoons curry powder
• 4 big sprigs fresh dill
• 1/2 small fennel bulb, thinly sliced
• 1 teaspoon ground cumin
• 1 teaspoon ground pepper
• 1 teaspoon ground turmeric
• 2 teaspoons Kosher salt
• 1 teaspoon fresh lemon juice
• 1 tablespoon mayonnaise, plus more for serving
• 1/4 cup olive oil
• 1/2 small red onion, thinly sliced
• 2 skinless, boneless chicken breasts (about 1 pound), halved horizontally
• 1 tablespoon sour cream
• 8 slices Sourdough bread