½cupMonterey jack cheeseor cheddar, or a combination of the two
Preheat the oven to broil on high and place a rack in the highest position.
Remove stem, seeds, and ribs from the poblano peppers. Cut the pepper into large pieces that will lay flat on a baking sheet. I do this bu cutting off the top, then cutting the body of the pepper into about four large chunks. You can press down on any pieces sticking up and it should crack the pepper enough to flatten it out. You just don’t want any pieces sticking up a lot higher than the rest of them.
Broil the flattened peppers skin-side up until blistered and charred, about five minutes. Immediately transfer the peppers to a bowl and cover tightly with plastic wrap. Allow the peppers to steam for about ten minutes. The skin should peel off easily Remove the skin from the peppers. It’s ok if a few bits remain.
Place the roasted peppers in a food processor along with the onion, cilantro, garlic, heavy cream, and sour cream. Process just until smooth.
In a 2 quart saucepan, heat butter over medium heat until melted. Whisk in flour and cook, whisking, for one minute. Add the poblano mixture and cook for a few minutes, whisking frequently.
Add vegetable stock and cheese. Let cook 5-10 minutes, until thickened, stirring frequently.
Tips for customizing
Swap the poblano peppers for red bell peppers to make a creamy red pepper sauce
Leave in some of the ribs and seeds on the poblano for extra heat
Use as enchilada sauce or drizzle on tacos or tostadas
Serve over beans, or meat eaters can spoon it over chicken or shrimp