Cut the chicken breasts into thin cutlets. To do this, please a chicken breast on a cutting board and use a sharp knife to slice it horizontally into two thin pieces (use the palm of your hand to hold the breast in place while cutting). Repeat this process with the rest of the chicken breasts.
Place one chicken breast in a plastic freezer bag. Using a meat pounder, a heavy skillet, or a rolling pin, gently pound the meat. Work slowly from side to side to ensure an even ¼-inch thickness. Repeat with the other outlets.
Season the chicken cutlets with the onion, garlic powder, salt, and pepper.
Beat the eggs in a large bowl and place the chicken breasts in this egg mixture.
Spread the breadcrumbs in a large dish. Have another large dish ready to put the chicken cutlets in after breading them.
With the help of your kitchen tongs (or with your hands), place one chicken cutlet in the breadcrumbs. Turn to coat both sides, and turn again (if needed) until it’s well covered with the breadcrumbs. You can lightly pat it, making sure the breadcrumb coating adheres to the chicken. Place the breaded chicken on the separate plate and keep breading the rest of the cutlets.
Heat the oil in a large frying pan over medium-high heat. Once the oil is hot, place the breaded chicken breasts in the pan to cook (without overcrowding the pan). Cook them for about 5 minutes per side and then place them on a plate that has been covered with napkins (in order to absorb any excess oil).