Preheat the oven to 400°F and line a baking sheet with parchment paper.
In a shallow bowl, combine the buttermilk with a pinch of salt, pepper, and garlic powder. Place the chicken breast in the bowl, ensuring it’s fully submerged, and let it marinate for at least 30 minutes.
In another bowl, add the whole wheat breadcrumbs seasoned lightly with salt and garlic powder.
Remove the chicken from the buttermilk, allowing the excess to drip off. Dredge the chicken in the breadcrumbs, pressing gently to ensure an even coating.
Place the coated chicken breast on the prepared baking sheet.
In a separate bowl, toss the broccoli and red bell pepper with olive oil, salt, and pepper. Spread the veggies around the chicken on the baking sheet.
Bake for 20-25 minutes, or until the chicken is cooked through and the coating appears crispy while the veggies are tender and slightly charred.
Remove from the oven, let rest for a few minutes, and serve warm.