If marinating in buttermilk first, soak for 4 hours to overnight. Then dredge in the chicken breeder or seasoned flour. If not soaking, dip in water, milk, or buttermilk then dredge in breading. Let the breaded chicken sit at room temp for about 10 minutes for the breading to set.
Fry in hot oil to cover until the chicken is golden brown & the inside juices run clear. Drain on paper towels or a wire rack over a baking sheet. Season with salt & pepper.
Reserve a couple tablespoons from the frying oil & sauté the diced jalapeños (adding some seeds if you want) for a minute, scraping the browned bits from the bottom. Whisk in the 2 tablespoons of flour, and cook for 30 to 60 seconds - then whisk in the milk. Cook on medium heat, whisking occasionally, until the gravy is thickened to your liking. Season the gravy with salt, pepper, & cayenne pepper (optional).
Serve the jalapeño gravy over top of the fried chicken breasts immediately.