Heat olive oil in a pan over medium heat. Once shimmering, add the diced onion and cook until translucent, about 10 minutes. Add garlic and continue to saute until fragrant, about 1 minute.
Add diced tomatoes, tomato paste, basil, oregano, salt, and pepper, and stir to combine. Bring sauce to a boil, then reduce to a simmer and continue to cook until it has thickened to your liking, about 15 minutes.
Serve warm over your favorite low carb noodles, veggies, or meat, and enjoy!
Notes
Nutritional information will vary depending on how much liquid you cook out of the sauce. I was able to make 4 cups of sauce using this recipe, making each serving ½ cup.