Split and remove cores from red peppers, and bake at 350°F for 45-60 minutes, or until skin is blackened and blistered. Set aside in a sealed container or zipper bag until cooled.
Meanwhile, also cut the tops off the garlic cloves and bake at 350°F for 60 minutes. They just need a little more time than the peppers, until they are softly golden browned.
After peppers and garlic have cooled, peel skins and place “meat” in blender with milk, sour cream, salt, and pepper. Pulse until smooth.
Slowly bring to a boil over medium-high heat. Simmer for 5-10 minutes to blend flavours