01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - In a bowl, whisk together Dijon mustard, maple syrup, olive oil, garlic, apple cider vinegar, salt, and black pepper. Add chicken breasts and toss to coat evenly. Allow to marinate for at least 15 minutes.
03 - Toss sweet potato cubes with olive oil, paprika, and salt on the prepared baking sheet. Spread in an even layer and roast for 25-30 minutes, flipping halfway through, until tender and golden brown.
04 - Heat a grill pan or skillet over medium heat. Remove chicken from marinade and grill or sear for 6-7 minutes per side until cooked through and juices run clear. Let rest for 5 minutes, then slice.
05 - In a small bowl, whisk together Dijon mustard, maple syrup, olive oil, lemon juice, and season with salt and pepper to taste.
06 - Arrange spinach or mixed greens in 4 large bowls. Top each with roasted sweet potatoes, cherry tomatoes, red onion, and sliced chicken. Drizzle with dressing and add optional toppings such as feta cheese, parsley, or pumpkin seeds.