(stolen mostly from http://www.whatwereeating.com/recipes/amandas-righteous-queso/)

1/2 small yellow onion (finely diced)
6 cloves of garlic minced into a paste
1 cup monterey jack (shredded)
1/2 cup sharp cheddar (shredded)
1/2 cup heavy cream
1 cup whole milk
teaspoon cumin
pinch cayenne
tbsp butter
tbsp flour
1/4 cup chopped pickled jalapenos
2 tbsp jalapeno juice
splash of beer
Salt and pepper
2 tbsp oil

First dice onion, mince garlic, and chop jalapenos. Place one mid-sized
sauce-pan on the stove for later and one small sauce-pan on a burner over
low to medium-low heat. Add oil to the small sauce-pan, preheat, then add
onion. Saute until onion is translucent, do not caramelize. Add garlic to
sauce-pan with onions, saute for a minute or until garlic has softened. Add
milk, heavy cream, cumin, cayenne and beer to the onions and garlic and raise
the heat to medium. Stir frequently until just under boiling. Do not allow
it to come to a boil.

Next, turn mid-sized sauce pan on, to a medium heat. Make a roux by: adding
1 tbsp of butter to sauce-pan, allow to melt but do not allow the butter to
brown. Add one tbsp of flour to the melted butter and stir frequently for 30
seconds to a minute, just to cook the flour. You do not want the roux to
take on any color. Slowly add small amounts of the hot milk to the roux,
stirring until smooth each time to prevent clumping. Once the milk has
completely been added to the roux, add 2 tbsp jalapeno juice, and chopped
jalapenos, and stir to combine. Stir frequently until the milk is nearly
up to a boil, then remove from heat and add monteray jack and cheddar.
Stir, then taste. Adjust flavor as necessary with salt and pepper, and
more cheese if you desire. Serve warm with tortilla chips. Garnish
with jalapenos or cilantro.