Heat oil: In a large saute' pan or medium saucepan, heat olive oil over medium-high until it's shimmering.
Add onion: Add the onion to the oil and cook until translucent, about 5 minutes.
Add some garlic: If using garlic, add garlic and cook until fragrant (no more than a minute, or it will brown).
Tomatoes: Add in the fresh tomatoes and the canned tomatoes. If you're using crushed tomatoes, stir it and combine. If you're using plum tomatoes, I break up the tomatoes with my hands, removing the hard end before adding to the sauce. Break up the tomatoes more with your wooden spoon and stir to combine.
Bring to a boil: Bring the sauce to a boil and use a wooden spoon to stir, breaking up the tomatoes while they’re cooking.
Lower heat: Once the sauce comes to a boil for a few minutes, lower heat to a simmer.
Season sauce: Season with the salt, and let the sauce cook and thicken.
Check the consistency of sauce: If it’s getting too thick, add a little bit of water (start with a ¼ cup).
Add fresh basil: Finally, stir in the fresh basil and stir to combine.
Simmer sauce: Let sauce simmer for 20 minutes total. Check the salt and add more if needed. Add hot pepper flakes, if you like it spicy.
Cook the ravioli: Boil large pot of salted water. If you're using homemade ravioli, depending on how thin or thick you made your pasta dough, it could take 2-5 minutes to cook. If you're using store-bought ravioli, check the cooking time on the package.
Strain: Scoop out the ravioli with a slotted spoon and add to a bowl or plates.
Add sauce: Spoon the sauce onto the ravioli and stir to gently combine.
Serve ravioli: Add in some more chopped fresh basil for serving. ENJOY!