Bring a pot of salted water to a boil and cook the penne according to package directions until al dente.
Reserve two tablespoons of the starchy pasta water before draining the noodles.
Season the chicken breast with sea salt, black pepper, and onion powder on both sides.
Heat olive oil in a large skillet over medium-high heat and sear the chicken until golden and cooked through.
Remove chicken from the pan, let it rest for two minutes, then slice into thin strips.
In the same skillet, reduce heat to medium and sauté minced garlic for thirty seconds until fragrant.
Add the baby spinach to the skillet and toss until just wilted.
In a small bowl, whisk together the Greek yogurt, parmesan cheese, and reserved pasta water until smooth.
Return the pasta and sliced chicken to the skillet, pour in the yogurt sauce, and toss gently to coat everything.
Serve immediately while the sauce is warm and creamy.