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, finely dice the red onion and mince the garlic cloves.
Heat the extra virgin olive oil in a large skillet over medium-high heat.
Add the red onion to the skillet and sauté for 3-4 minutes until they begin to soften and caramelize.
Add the ground turkey Italian sausage to the skillet, breaking it up with a wooden spoon, and cook until browned and cooked through.
Stir in the minced garlic, dried oregano, sea salt, and black pepper, cooking for 1 minute until fragrant.
Pour in the tomato puree and a splash of the pasta cooking water, stirring to create a light sauce.
Add the fresh baby spinach to the skillet and stir until just wilted.
Drain the penne and add it directly to the skillet, tossing well to coat the pasta in the sausage and onion mixture.
Garnish with freshly chopped parsley and serve immediately while hot.