Bring a large pot of salted water to a boil and cook the whole grain penne according to package directions until al dente.
Reserve 0.25 cup of the starchy pasta water before draining the noodles.
Season the chicken breast with half of the sea salt and black pepper.
Heat olive oil in a large skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden and cooked through.
Remove chicken from the pan, let it rest for 3 minutes, then slice into bite-sized strips.
In the same skillet, reduce heat to medium and sauté the minced garlic for 30 seconds until fragrant.
Add the baby spinach to the skillet and toss until just wilted.
In a small bowl, whisk together the Greek yogurt, lemon juice, lemon zest, fresh parsley, fresh dill, and remaining salt and pepper.
Return the cooked pasta and sliced chicken to the skillet, then pour in the yogurt mixture and the reserved pasta water.
Toss everything together over low heat for 1 minute until the sauce is creamy and coats the pasta evenly.