Rinse the quinoa under cold water and place in a pot with the chicken broth.
Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the liquid is fully absorbed.
Season the chicken breasts evenly with the sea salt and black pepper.
Heat 6 tablespoons of the olive oil in a large skillet over medium-high heat, working in batches if necessary.
Sear the chicken for 6-8 minutes per side until the exterior is golden and the internal temperature reaches 165°F.
Remove the chicken from the skillet and let it rest on a cutting board for 5 minutes before slicing.
In the same skillet, add the remaining 3 tablespoons of olive oil and the minced garlic, sautéing for 1 minute until fragrant.
Add the baby spinach to the skillet and toss until it is just wilted and bright green.
Fluff the cooked quinoa with a fork and stir in the wilted spinach, lemon juice, and chopped parsley.
Divide the quinoa mixture into six equal portions and top each with a sliced chicken breast to serve.