01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - Rinse barley under cold water. In a medium saucepan, combine barley and broth. Bring to a boil, reduce heat, cover, and simmer for 25 to 30 minutes until tender. Drain any excess liquid.
03 - Using a vegetable peeler, shave carrots lengthwise into ribbons. Toss carrot ribbons and red onion with 1 tablespoon olive oil, salt, and pepper. Spread evenly on the prepared baking sheet. Roast for 15 to 18 minutes, stirring halfway, until carrots are tender and slightly caramelized.
04 - In a small bowl, whisk together remaining olive oil, lemon juice, Dijon mustard, honey, garlic, salt, and pepper until emulsified.
05 - In a large bowl, combine cooked barley, roasted carrot ribbons, red onion, and baby spinach. Drizzle with dressing and toss gently until well mixed.
06 - Serve warm, garnished with parsley, feta cheese if using, and pumpkin seeds.