Bring a large pot of salted water to a rolling boil. Add the linguine and cook according to package directions until al dente. Before draining, reserve 1 cup of the pasta cooking water. Drain the pasta and set aside.

While the pasta is cooking, pat the shrimp dry with paper towels. In a medium bowl, toss the shrimp with 1 tbsp olive oil, 0.5 tsp salt, 0.25 tsp black pepper, and red pepper flakes (if using).

Heat a large skillet or Dutch oven over medium-high heat. Add the seasoned shrimp in a single layer (cook in batches if necessary to avoid overcrowding) and cook for 2-3 minutes per side, until pink and opaque. Remove the shrimp from the skillet and set aside.

In the same skillet over medium heat, add 2 tbsp olive oil and 1 tbsp butter. Once the butter is melted, add the minced garlic and sauté for 1 minute until fragrant, being careful not to burn it.

Pour in the chicken broth and bring to a simmer, scraping up any browned bits from the bottom of the pan. Stir in the heavy cream, chopped sun-dried tomatoes, dried oregano, and a pinch of salt and pepper. Bring the sauce to a gentle simmer and cook for 2-3 minutes, allowing it to slightly thicken.

Reduce the heat to low. Add the fresh spinach to the sauce, stirring until it wilts, about 1-2 minutes.

Stir in 0.5 cup grated Parmesan cheese until melted and smooth. If the sauce is too thick, add a splash of the reserved pasta cooking water until it reaches your desired consistency.

Add the cooked linguine and cooked shrimp back into the skillet with the sauce. Toss gently to coat everything evenly. Stir in the 0.25 cup fresh basil. Taste and adjust seasonings (salt, pepper) as needed.

Serve immediately, garnished with extra fresh basil and grated Parmesan cheese, if desired.