Pour tomatoes out of the can and crush with your hands. Add water to the can, using it to get all the tomato goodness out of it. Set aside.
Heat up olive oil in a skillet over medium heat. Once hot add in garlic and cook for a minute or so, not allowing it to brown.
Pour in crushed tomatoes and reserved water, along with salt, red pepper flakes and oregano. Place the basil spring whole in the center of the sauce, allowing it to submerge as it cooks. If no fresh basil is at hand, use dried.
Turn the heat down to low and simmer for 15 minutes, or until thickened and the oil on the surface is a deep yellow color.
Discard basil, mix thoroughly and use as needed.
Please note that nutrition facts are estimated for the entire batch (which yields roughly 3 1/2 cups).