Season shrimp with salt and ground black pepper. Set aside.
Cook dry spaghetti in boiling salted water until al dente. Reserve ½ cup pasta water. Drain cooked spaghetti. Set aside.
In a heated skillet with olive oil, shallow fry shrimp for 1 to 2 minutes. Turn and continue to fry shrimp for 1 minute or until the color changes to pink or orange. Do not overcrowd. Drain shrimp in paper-lined towel.
In the same skillet, retain 1 to 2 tablespoons of olive oil. Melt butter.
Sauté onions until translucent. Add garlic and continue to sauté for 1 to 2 minutes or until fragrant. Avoid burning the garlic.
Add cherry tomatoes and sprinkle ground black pepper. Simmer undisturbed for 3 to 5 minutes.
Add fresh basil and red pepper flakes. Sprinkle salt and ground black pepper, according to taste. Sauté for another minute.
Add shrimp, a bit of pasta water, and al dente spaghetti. Gently toss until shrimp and pasta are warm, for about 1 minute.
Sprinkle Parmesan cheese. Give another gentle toss.
Garnish with lemon wedges, fresh basil, and sprinkle with some Parmesan cheese.
Notes
Cook shrimp in batches and do not overcrowd in the pan.Do not overcook shrimp. Shrimp becomes rubbery when overcooked.