Step 1: Prepare and Roast the Vegetables

1. Preheat the oven to 400°F (200°C) and line two baking sheets with parchment paper.
2. Place the beet cubes on one baking sheet and the sweet potato cubes on the other to prevent the beets from staining the sweet potatoes.
3. Drizzle each vegetable batch with 1 1/2 tablespoons of olive oil, then sprinkle with salt, black pepper, and garlic powder. Toss to coat evenly.
4. Roast in the preheated oven for 25-30 minutes, or until both the beets and sweet potatoes are tender and caramelized. Be sure to stir halfway through to ensure even roasting.

Step 2: Make the Maple Bacon Drizzle

1. While the vegetables are roasting, heat a skillet over medium heat and add the chopped bacon. Cook until the bacon is crispy, about 8-10 minutes. Remove the bacon with a slotted spoon and set it on a paper towel to drain.
2. Discard most of the bacon grease, leaving about 1 tablespoon in the skillet.
3. Add maple syrup, balsamic vinegar, and Dijon mustard to the skillet. Whisk to combine and cook for 2-3 minutes, until the sauce thickens slightly. Remove from heat and set aside.

Step 3: Assemble the Bowl

1. Divide the mixed greens evenly among four serving bowls.
2. Top each bowl with a generous portion of roasted beets and sweet potatoes.
3. Sprinkle crumbled feta cheese, chopped parsley, and toasted nuts (if using) over the vegetables.
4. Drizzle the maple bacon sauce generously over the top of each bowl.