I've come across various recipes for chile con queso in my time, and aside from the tried and true method which entails a pound of Velveeta, a can of extra hot Rotel, and a can of black beans heated until the orange stuff melts (for which I must confess a weekness), this one works about the best. Fans of French cooking will recognize immediately that it's simply a jazzed up rendition of a bechamel sauce and they'd be right, except that this stuff is so much more than the sum of its parts. Before we get started, a few notes: The whole idea is to produce a cheese dip/sauce that's both smoky and spicy, so I personally recommend using chipotles that have been dried and bagged as opposed to the ones canned in adobo sauce (which are fine, but what you'll really be doing is adding adobo flavor to your queso, which will markedly change its character). Before you add them to the queso, you should do one of the following to your chipotles if using dried ones: A) Stem them and either whack them in a blender or food processor until they're basically powder or grind them to a pulp with a mortar and pestle (of course, you can seed and de-vein them if a mild dip is what you're after). B) Bring some water (the volume of water isn't critical as long as you have enough to cover the chipotles) to a boil and remove from heat. Drop in your chiles, using a plate or some other improvised kitchen implement to keep them submerged, and let soak for around 15 minutes before stemming, seeding and de-veining (if desired) and chopping. This will soften them up so they're easier to work with, and also has the benefit of muting some of the heat. Unfortunately, it does the same to the smokey flavor as well. If you're using jalapeños, I'd recommend roasting them either in a broiler or on your range top until the skin is blackened. Remove the skin, stem, seeds and vein (again, for a milder dip), chop, and use as indicated. Finally, I recommend going with either asadero or an extra sharp white cheddar. Monterrey jack works great because it melts really well, but it's so mild in flavor that it takes a back seat to the other ingredients. What we want is first and foremost a cheese dip, so a more piquant cheese like the ones mentioned above is probably best.