Preheat your oven to 400°F and line a baking sheet with parchment paper.
Rinse the brown rice under cold water, then combine with 0.5 cup water in a small pot, bringing to a boil before simmering covered for 35 minutes until tender.
Mince the garlic and finely chop the fresh rosemary.
In a small bowl, whisk together 0.25 tablespoon of olive oil, lemon juice, minced garlic, rosemary, sea salt, and black pepper.
Place the chicken breast on the baking sheet and coat thoroughly with the lemon-herb marinade.
Trim the woody ends off the asparagus, toss with the remaining 0.25 tablespoon of olive oil, and arrange them on the baking sheet next to the chicken.
Roast for 18 to 22 minutes until the chicken reaches an internal temperature of 165°F and the asparagus is slightly charred.
Slice the roasted chicken and serve it alongside the asparagus over the bed of fluffy brown rice.