Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper. Place the pounded chicken breasts on a cutting board and pat them very dry with paper towels.
Step 2: Set up your dredging station: In a shallow dish, combine flour, 1/4 teaspoon salt, and 1/8 teaspoon black pepper. In a second shallow dish, whisk eggs with water/milk. In a third shallow dish, combine crushed pretzels, garlic powder, paprika, remaining 1/4 teaspoon salt, and 1/8 teaspoon black pepper.
Step 3: Dredge each chicken piece: First, coat in flour, shaking off excess. Next, dip in egg wash, letting excess drip off. Finally, press firmly into the pretzel mixture, ensuring a thick, even coating on all sides.
Step 4: Place the coated chicken on one side of the prepared baking sheet. Drizzle or spray chicken lightly with 1 tablespoon olive oil. Arrange broccoli, bell peppers, and red onion on the other side of the baking sheet. Drizzle vegetables with the remaining 1 tablespoon olive oil and season with salt and pepper.
Step 5: Roast for 20-25 minutes, flipping the chicken and stirring the vegetables halfway through, until the chicken reaches an internal temperature of 165°F (74°C) and the pretzel crust is golden and crispy. Vegetables should be tender-crisp.
Step 6: While the chicken roasts, prepare the Honey Mustard Dressing: In a small bowl, whisk together Dijon mustard, honey, apple cider vinegar, 1 tablespoon olive oil, and a pinch of salt and pepper until smooth. Taste and adjust seasonings as needed.
Step 7: Once cooked, remove chicken from the oven and let it rest for a few minutes before slicing into strips or cubes. Divide cooked quinoa or rice among four serving bowls.
Step 8: Top each bowl with sliced pretzel chicken and a generous serving of roasted vegetables. Drizzle generously with the homemade honey mustard dressing and garnish with fresh parsley or chives, if desired. Serve immediately.