Preheat oven to 450F. Line a baking pan with foil and place poblanos on pan
Roast until charred and soft, about 20 minutes
Peel, and remove core and most of the seeds and cut into strips
Puree in food processorvor blender until smooth
In a saucepan heat butter and add shallots and garlic and soften
Add remaining ingredients except peppers and bring to a simmer
Simmer about 10 minutes at a slow simmer until just starting to get thicker, add pureed peppers and heat,
Cool mixture slightly then return to clean food processor or blender for a smooth sauce. Reheat before serving, adding broth or more cream by dropfulls if it gets to thick
This sauce is good with grilled and roasted meats, seafood and vegetables and goes with various appetizers that are good with dipping sauces
