Tomato-Jalapeno Enchilada Sauce

In a blender, combine tomatoes, onion, and jalapeno. Puree until smooth. Season with salt and pepper. In a medium pot, heat oil over high until shimmering. Add tomato mixture and simmer, stirring, until thickened, 5 to 10 minutes. Remove from heat and stir in thyme, vinegar, and sugar. Season to taste with salt and pepper.