Bring a large pot of salted water to a boil and cook the whole wheat penne according to package directions 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 sauté the chicken until golden brown and cooked through, about 5-6 minutes per side.
Remove the chicken from the skillet and set aside to rest, then slice into thin strips.
In the same skillet, reduce heat to medium and add the minced garlic, sautéing for 1 minute until fragrant.
Whisk together the Greek yogurt, chicken broth, and lemon juice in a small bowl, then pour into the skillet.
Stir the sauce constantly for 2 minutes until slightly thickened, ensuring it does not reach a hard boil to prevent curdling.
Add the cooked pasta, sliced chicken, and baby spinach to the skillet, tossing until the spinach is wilted and everything is coated in sauce.
Season with the remaining salt and pepper, then garnish with fresh parsley and grated parmesan cheese before serving.