Bring a large pot of salted water to a boil and cook the penne pasta until al dente according to package directions.
While the pasta cooks, season the chicken breast on both sides with sea salt, black pepper, and dried oregano.
Heat the extra virgin olive oil in a large skillet over medium-high heat.
Place the chicken in the skillet and sear for 5-7 minutes per side until golden brown and the internal temperature reaches 165 degrees Fahrenheit.
Remove the chicken from the pan and let it rest for 3 minutes before slicing into thin strips.
In the same skillet, add the minced garlic and sauté for 30 seconds until fragrant.
Add the baby spinach to the skillet and toss for 1 minute until just wilted.
Drain the pasta, reserving a splash of pasta water, and add the pasta to the skillet with the spinach and garlic.
Add the sliced chicken, lemon juice, and fresh parsley to the skillet, tossing well to coat all ingredients.
Serve immediately topped with the grated parmesan cheese.