Heat the oil in a heavy-bottomed saucepan over medium heat until hot and shimmering. Add the onion and cook, stirring occasionally, for 7-9 minutes, or until golden brown.
Add the whole tomatoes and their juices, tomato sauce, vinegar, brown sugar, orange juice, molasses, sweet paprika, chili powder, salt, freshly cracked black pepper, and liquid smoke. =
Bring to a boil, then reduce the heat to the lowest setting and simmer, uncovered and stirring occasionally, until thickened, 2 1/2 hours.
Remove from the heat and cool for a bit. Blend with an immersion blender or blender until blended smooth.
Transfer to a jar and use immediately or store sealed in the refrigerator for up to two weeks.