Step one: sear the cubed beef in a quantity of bacon fat. I happen to like the way the bacon fat flavors the dish, and since I'm not including any pork this time, the fat will compensate. Searing the cubed beef also improves the flavor, by caramelizing the meat.
I do this over fairly high heat, in batches. The seared beef is then set to rest on the side, not in the pan.
Meat all seared, I've now turned the heat to low, and added to the pan a yellow onion, roughly chopped, three pasilla chilis, roughly chopped, and three jalapenos, more finely chopped. I covered the pan, and went to wash my hands.
THIS IS AN IMPORTANT STEP! Have you ever chopped up a fresh chili and accidentally rubbed your eyes, or your nose, or any other sensative part of your body? DOING THIS CAN CAUSE INSTANT AGONY!!! Trust me, I did it once. The stuff in the chilis that causes the heat can really hurt you.