Heat 1 tbsp of the butter in a large, wide skillet or Dutch oven over medium-high heat. Add the onions and cook for 2 minutes.
Add the ground turkey and cook, breaking it up with a spoon, until browned and cooked through, about 6–7 minutes.
Add all 4 minced garlic cloves and cook for 1–2 minutes, stirring constantly, until fragrant. Be careful not to let it brown.
Season with salt, black pepper, Italian herbs, smoked paprika, basil, garlic powder, onion powder and red pepper flakes if using. Stir well to coat everything in the spices.
Pour in the broth and bring to a rolling boil, scraping up any browned bits from the bottom of the pan.
Add the dry penne and stir to submerge. Reduce heat to a steady simmer, cover partially, and cook for about 10–12 minutes, stirring every 2–3 minutes to prevent pasta from sticking to the bottom of the pan and until the pasta is al dente and has absorbed most of the broth.
Reduce heat to low and pour in the heavy cream. Stir and let everything come together for 1–2 minutes until the sauce is creamy and coats the pasta.
Remove the pan from the heat completely. Sprinkle in the shredded sharp cheddar and stir gently until melted. Taste and adjust seasoning if needed.
Serve immediately, garnished with chopped parsley, a pinch of smoked paprika, and red pepper flakes if desired.