[header] How to make barbacoa [title] Puree the sauce ingredients. [step] Combine the chopped onions, olive oil, garlic, cumin, oregano, chiles, cider vinegar, and salt in a blender or food processor. Blend the ingredients together at medium to high speed until a thick puree forms. 
[substeps] Do not drain the adobo sauce from the chipotle chiles before adding them. You should pour the sauce into the blender along with the chiles.