1 tablespoon olive oil 1 tablespoon minced garlic (about two or three large cloves) 1 teaspoon dried oregano or 1 tablespoon fresh chopped oregano (if using fresh, add at the end of the cooking time) 2 cans (14.5 ounces each) diced tomatoes (undrained) or 2 pounds diced fresh tomatoes 1 teaspoon sugar 1/2 teaspoon red pepper flakes (this makes for a lot of heat, which we love, but I recommend you start out with 1/4 teaspoon or even just a generous pinch if you're unsure) 1/2 teaspoon kosher salt Black pepper to taste

In a medium saucepan over low heat, warm the olive oil.
Add the garlic and cook, stirring, for about a minute. If you're using dried oregano, add that along with the garlic. If you're using fresh, add it to the sauce at the end of the cooking time.
Increase the heat to medium. Add the tomatoes, sugar, red pepper flakes, salt, and black pepper.
Leave over medium heat, stirring occasionally, until boiling. Reduce heat to low for a nice simmer.
Simmer uncovered for 90 minutes.
Stir in fresh oregano, if using.
Allow the sauce to cool to a safe temperature and then, using an immersion blender or working in batches with a blender,
If using fresh oregano, stir that in after the hour and a half cooking time.