Chipotle Sauce

Directions

1. 1
   Line heavy large skillet with foil; heat over medium heat.
2. 2
   Place onion and garlic in skillet; cook until onion softens and blackens in spots, turning often with tongs, about 15 minutes.
3. 3
   Transfer onion and garlic to medium bowl.
4. 4
   Peel garlic.
5. 5
   Place same foil-lined skillet over medium-high heat.
6. 6
   Working in 2 batches, cook tomatoes in skillet until tender and skins blister and blacken, turning occasionally, about 20 minutes.
7. 7
   Transfer to large bowl; cool and peel.
8. 8
   Working in batches, puree tomatoes, onion, garlic, and chiles in blender until smooth.
9. 9
   Heat oil in heavy large deep skillet over medium-high heat.
10. 10
    Carefully add tomato puree to skillet (mixture will bubble vigorously).
11. 11
    Stir in salt.
12. 12
    Reduce heat; simmer gently until sauce thickens slightly, stirring often, about 15 minutes.