Coat the poblanos with olive oil. Season them with a little salt and pepper. In your oven under an oven broiler or on a very hot grill roast the poblanos. The skin should be completely black when finished. Remove from heat and let cool. Remove the skin, stim and seeds. Give the peppers a fine dice.
In a medium heavy bottomed pot over medium heat add the butter. Once melted at the onions (2-3 minutes). Cook until they are translucent and then add the beer. When the beer comes to the simmer add the cream and cheese stirring every couple of minutes.
The cheese sauce will come together in 5-8 minutes. Once that is complete bring the stovetop to a low setting and add everything but the adobo sauce.
Place the queso in a serving dish. Toss the brisket in the adobo sauce place the brisket on top of the queso.