Chicken Souvlaki

INGREDIENTS

2 cups

plain yogurt

cucumber, halved lengthwise, peeled, seeded, and grated

1 1/4 tsp

salt

1 clove

garlic, minced

Fresh-ground black pepper

1/4 tsp

dried dill

2 tbsp

olive oil

1 1/2 tsp

lemon juice

1 tbsp

dried oregano

1 1/3 lb

boneless, skinless chicken breasts (about 4), cut into 1-inch cubes

pocketless pitas

6 tbsp

butter, at room temperature

small onion, cut into thin wedges

tomatoes, cut into thin wedges

1/3 cup

black olives, such as Kalamata, halved and pitted