01 - Preheat oven to 425°F. Line two baking sheets with parchment paper.
02 - Place diced beets on one baking sheet and diced sweet potatoes on the other. Drizzle each with 1 tablespoon olive oil and a pinch of salt, then toss to coat and spread in a single layer.
03 - Roast sweet potatoes for 25 to 30 minutes and beets for 35 to 40 minutes, until tender and lightly caramelized. Allow vegetables to cool slightly before assembling.
04 - In a mixing bowl, whisk together Greek yogurt, lemon juice, remaining olive oil, honey or maple syrup, Dijon mustard, salt, and black pepper until smooth.
05 - In a large salad bowl, arrange arugula or mixed salad greens as the foundation.
06 - Top greens with roasted beets, roasted sweet potatoes, sliced red onion, and crumbled feta cheese.
07 - Drizzle with creamy yogurt dressing. Gently toss to combine all ingredients evenly.
08 - Scatter toasted pumpkin seeds or walnuts and chopped fresh herbs over the top just before serving.