If using fresh tomatoes, first blanch the tomatoes in boiling water for 30-60 seconds. Once the tomato skins "burst" and begin to peel away from the flesh of the tomato, remove the blanched tomatoes from the boiling water and submerge them into an ice water bath to remove the skins. Transfer the skinned tomatoes to a large bowl and crush with clean hands. (See video.)
Add olive oil to a large saucepan, Dutch oven, or stockpot. Heat to medium and add garlic.
Sauté garlic until golden and fragrant, but do not allow the garlic to brown. This process takes approximately 2-3 minutes.
Add crushed tomatoes to your pan along with salt, black pepper, red pepper flakes (if using), oregano (or basil), bay leaves (if using). Stir well.
Bring tomatoes up to a medium-high simmer where you see a bit of bubbling. Be sure to stir the tomatoes to ensure that nothing sticks to the bottom.
Turn heat to medium-low, cover pan, and allow the mixture to simmer for one hour. If you are using canned tomatoes, you can reduce the simmering time by 15 minutes, bringing the simmering time down to 45 minutes.
After the simmering time has finished, your marinara sauce is ready to be served.
If refrigerated in an airtight container, your marinara should stay fresh for approximately 7-10 days.
If frozen in an airtight container or freezer-proof bag, your marinara should stay fresh for approximately 3 months. When ready to use, defrost in the refrigerator.