Cook the pasta: Boil a large pot of salted water and cook spaghetti until al dente (8-10 minutes). For extra flavor, add a drizzle of olive oil and fresh herbs. Reserve 1 cup of pasta water, then drain and set aside.
Prepare the shrimp: Rinse under cold water and pat dry with a paper towel for better searing.
Sauté the shrimp: Heat butter and olive oil in a skillet over medium heat. Add shrimp in a single layer, season with Italian seasoning, salt, pepper, and red pepper flakes. Cook for 2-3 minutes per side until pink and curled. Remove and set aside.
Make the garlic butter sauce: Lower the heat, add minced garlic to the pan, and stir for 30 seconds until fragrant.
Toss everything together: Add cooked pasta to the skillet and toss in the garlic butter sauce. Gradually add reserved pasta water, a few tablespoons at a time, until the sauce coats the pasta.
Add the shrimp: Return shrimp to the pan and mix well. Adjust seasoning and sprinkle extra red pepper flakes if desired.
Garnish and serve: Remove from heat, stir in fresh herbs, and serve with a squeeze of lemon juice and optional parmesan cheese.