Boil a large pot of salted water. Cook the 12 oz linguine pasta according to the package directions until al dente. Reserve 1/2 cup of pasta water, then drain the noodles.

While the pasta cooks, heat 1 tbsp of olive oil in a large skillet over medium-high heat. Season the 16 oz chicken breasts evenly with 1 tsp smoked paprika, 1/2 tsp kosher salt, and 1/2 tsp black pepper.

Cook the chicken in the skillet for 5 to 7 minutes per side until the internal temperature reaches 165°F. Remove the chicken from the pan, let it rest for 5 minutes, and then slice it into strips.

Reduce the skillet heat to medium. Add the remaining 1 tbsp of olive oil and 1 tbsp butter. Sauté the 1/2 cup diced yellow onion for 3 to 4 minutes until translucent.

Stir in the 2 tbsp minced garlic and 1 tsp red chili flakes. Cook for 1 minute until fragrant, then mix in the 1 tbsp tomato paste and cook for 1 additional minute.

Pour the 14.5 oz canned diced tomatoes and 1 cup heavy cream into the skillet. Simmer the creamy tomato sauce gently for 5 minutes.

Stir in the 1/2 cup grated Parmesan cheese until completely melted. If the sauce becomes too thick, pour in a small amount of the reserved pasta water.

Add the drained linguine and sliced grilled chicken into the sauce, tossing well to coat. Garnish with 1/4 cup fresh parsley before serving.