Heat the olive oil in a saucepan over medium heat. Add the diced onion and cook until softened, about 3-5 minutes. Stir in the minced garlic and cook for another 30 seconds until fragrant.
Add the tomato puree, tomato paste, apple cider vinegar, honey, salt, oregano, and pepper. Stir well and let it simmer for about 15-20 minutes, stirring occasionally.
Blend the mixture with an immersion blender or transfer it to a regular blender to make it smooth.
Taste and adjust seasoning if needed. Let it cool, then store in an airtight container in the refrigerator for up to 2 weeks.