Scrub the potatoes with a vegetable brush. Slice into about 1/2" slices then cut in strips. Chop the onions and the jalapeños.

Put the bacon fat into the skillet and heat until hot. Add the potatoes and onions and cook without turning for 5-8 minutes. When they look like they are starting to brown on the bottom, add the jalapeño and about 1/3-1/2 cup water to the pan. Cover the skillet and cook for about 12-14 minutes or until the potatoes are tender when pierced with a knife. When tender, remove lid and continue to fry until potatoes are browned on all sides.

Season with salt and pepper and serve.