Warm the olive oil in a Dutch Oven over medium heat. Add the onions and continue cooking until they soften and become translucent, for about 10 minutes. Then, stir in the tomato paste and cook for 30 seconds.
Add the sauce from the can to the Dutch oven and crush the tomatoes into the pot.
Stir salt and red pepper flakes into the tomato mixture.
Reduce the heat, cover with the lid slightly ajar, and gently simmer for 15-20 minutes until the tomatoes break down. Adjust the heat if the mixture begins bubbling too much.
OPTIONAL - Use an immersion blender to incorporate the sauce until smooth.
Garnish the sauce with fresh basil, and enjoy!
Notes
Yields: 2 cups Expert Tips:
Begin with quality ingredients! Fresh tomatoes are the key to great-tasting tomato sauce; that's why I swear by San Marzano tomatoes.
If tomato sauce is too acidic for you, add a small carrot while the sauce simmers; the sweetness of the carrot will release throughout the cooking process, and that's enough to balance the acidity of the tomatoes.
Nutrition Disclosure:
The nutritional information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for professional advice.