Add 1/2 cup plain Greek yogurt, 3 tablespoons olive oil, 2 tablespoons harissa paste, 2 tablespoons lemon juice, 1 tablespoon honey, 4 cloves garlic, 1 teaspoon salt, and 1/4 teaspoon black pepper to a large bowl and whisk until well mixed.
Place 1 pound boneless skinless chicken thighs in the marinade and rub to coat. Cover the bowl with plastic wrap, and store in the fridge for at least 30 minutes and no longer than 24 hours.
Make the yogurt sauce by adding 1/2 cup plain Greek yogurt, 2 tablespoons fresh cilantro, 2 tablespoons lemon juice, 1 clove garlic, and 1/2 teaspoon salt into a food processor. Cover and puree until smooth. Then store in the fridge until needed. This sauce gets better as it sits, so don't wait to mix it.
When you're ready to cook the chicken, preheat the grill to 400 degrees F.
Use the tongs to take the chicken out of the marinade and place it onto the grill. Cook for 5-6 minutes, flip, and cook for another 5-6 minutes until the chicken has light char marks and the thickest part reaches 165°F.
Remove from the grill plate with your favorite sides. Drizzle the chicken with yogurt sauce, and serve the extra on the side for dipping.
Notes
Nutritional information includes 6 tablespoons of yogurt sauce per person.You can swap boneless thighs for breasts, but reduce cook time to 3-4 minutes per side. For indoor cooking, use a grill pan over medium-high heat until the internal temp reaches 165°F.