Heat the olive oil in a large skillet over medium heat. Add the chopped onion and cook for about 3-4 minutes, until it becomes translucent.
Stir in the minced garlic and red pepper flakes. Cook for another 1-2 minutes, being careful not to let the garlic burn.
Pour in the crushed tomatoes, 1/2 cup water, and white wine (if using). Season with salt and black pepper. Bring the mixture to a simmer, then reduce the heat to low and let it cook for about 30 to 40 minutes, allowing the flavors to meld and the sauce to thicken slightly. Stir occasionally.
While the sauce is simmering, prepare your seafood if you haven't already. If using shrimp, make sure they are peeled and deveined.
Add the shrimp (or your choice of seafood) to the simmering sauce. Cook for about 4-5 minutes, or until the seafood is cooked through and opaque. Be careful not to overcook it.
Stir in the fresh basil and parsley. Taste and adjust the seasoning with more salt and red pepper flakes if needed and a drizzle of olive oil if desired.
Serve the Fra Diavolo sauce over cooked pasta.
Notes
The nutrition estimate does NOT include pasta and is based on using 1-pound shrimp.