To a large skillet on medium high heat, add the oil, once hot, add the tomatoes, serranos & half the onion. Cool for 5-7 minutes or until some of the veggies are getting browned.
Step 2
Add in the garlic, cook for 4-5 more minutes, then some Chiles de Arbol and cook for another 4-5 minutes.
Step 3
Add in half the can of beer, let it cook/simmer for 5 minutes.
Step 4
Let the mixture cool down slightly before adding to a blender or food processor. Add the salt & blend until combined, try to leave it slightly chunky still.
Step 5
Pour the salsa into a bowl, then mix in the remaining chopped onion, cilantro, about another 1/4 cup of the beer and the juice of one lime. Stir to combine and adjust seasonings if needed.