Preheat the grill or grill pan over medium-high heat.
Season the chicken breasts with olive oil, salt, and pepper on both sides.
Grill the chicken for about 6-7 minutes on each side, or until the internal temperature reaches 165°F (75°C). Remove from the grill and let rest for a few minutes before slicing.
In a medium saucepan, bring water to a boil. Add the broccoli florets and blanch for about 3-4 minutes until bright green and tender-crisp. Drain and set aside.
In the same saucepan, combine the heavy cream, minced garlic, lemon juice, garlic powder, and Parmesan cheese (if using). Cook over medium heat, whisking frequently, until the sauce is warmed through and slightly thickened (about 5 minutes).
Slice the grilled chicken breast into strips.
To assemble the bowls, divide the blanched broccoli evenly among the serving bowls. Top with the sliced grilled chicken and drizzle with the creamy garlic sauce.
Serve warm, garnished with additional Parmesan cheese if desired.