Bring a large pot of salted water to a boil and cook the whole wheat penne according to package instructions until al dente.
While the pasta cooks, season the chicken breast with half of the sea salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden brown and cooked through.
Remove the chicken from the skillet and let it rest for 2 minutes before slicing into thin strips.
In the same skillet, reduce the heat to low and add the minced garlic, sautéing for 30 seconds until fragrant.
Whisk in the Greek yogurt, lemon juice, lemon zest, and the remaining salt and pepper to create a smooth, creamy sauce.
Add the cooked pasta, sliced chicken, and baby spinach to the skillet, tossing gently until the spinach is wilted and the pasta is well coated.
Garnish with freshly chopped parsley and serve warm.