Mix the yogurt, garlic, lemon, salt, and pepper in a small bowl. Set aside.
Chicken
To prep the chicken, first slice the breasts into cutlets. Place the chicken breast flat on a cutting board. Hold a sharp knife parallel to the cutting board at the thickest part of the chicken. Carefully slice horizontally through the chicken, starting at one edge, and continuing all the way through.
Place the cutlets on a plate or in a bowl and coat the olive oil, paprika, dill, salt, and pepper.
Heat a grill pan over medium heat.
Grill the buns once the pan is hot. Drizzle each bun half with olive oil and heat the grill for 3-4 minutes, until hot and marked with grill lines.
Cook the chicken for 3-4 minutes on the first side and 2-3 minutes on the second side, depending on how big they are. Chicken is done when it reaches an internal temperature of 165°F (74°C).
Make the Sandwich
Spread the bottom of the bun with garlic yogurt. Add spinach, and then the chicken cutlet. Top with sprouts, more sauce if you want it, and the top bun. Serve hot.
Notes
Store leftover cooked chicken in an airtight container in the fridge for up to 3 days.Keep the yogurt sauce in a separate container, sealed, for 3 to 4 days.Don’t store the assembled sandwich, as ciabatta can get soggy fast.