I have the good fortune to live a few miles from a mercado that purveys fresh serrano chiles at $2 per 3 pound bag. I call the store the Mexitalian Store because it carries products from both cultures, each culture having its own aisle of shelves for packaged goods.
I like to use deep fried green serrano chiles as a condiment in my fusion sandwiches with Italian cold cuts on seeded rye bread.
Remove the stems from the chiles and slice the chiles lengthwise. Do not remove the seeds unless you wish to reduce the heat. Using good quality olive oil, pour oil into a high sided sauce pan, and heat to a boil. Gently add some of the sliced chiles to the hot oil. When the chiles are limp, they are done so remove them from the oil. Repeat the adding of chiles to the oil until all the chiles are fried. Add slices of garlic cloves to the oil with the last batch of chiles.
Store the chiles in jars (I'm a recycler of wide-mouth jars from other products), and refrigerate until use.
When the chiles are all gone, use the oil for other culinary purposes instead of discarding it.