Cook the Pasta: Bring a pot of salted water to a boil. Cook pasta until al dente. Reserve some pasta water, then drain.
Prepare the Shrimp: Pat shrimp dry and season with smoked paprika and garlic salt. Set aside.
Cook the Guanciale: Heat a large skillet over medium heat. Add guanciale and cook until crispy. Remove and set aside, leaving the rendered fat. If using olive oil instead, heat it in the pan.
Sauté the Aromatics: Add diced onion to the skillet and cook for 2–3 minutes until softened. Stir in garlic and cook for 30 seconds until fragrant.
Build the Sauce: Add smoked paprika, Italian seasoning, dried parsley, and cayenne. Stir briefly, then pour in heavy cream. Bring to a gentle simmer and stir in Parmesan until smooth. Season with salt and pepper.
Cook the Shrimp: Add shrimp to the sauce and cook for 2 minutes per side until pink and cooked through. Return guanciale to the pan.
Combine with Pasta: Add cooked pasta to the skillet and toss to coat. Add a splash of reserved pasta water if needed to loosen the sauce.
Serve: Divide into plates and garnish with fresh parsley. Serve immediately.