Take your knife and cut a pocket at the thickest part of the chicken breast do this to all (10) of the chicken breasts, take feta cheese block and cut into 10 slices and then in half again lengthwise.
Mix breadcrumbs, garlic powder, parmesan cheese, salt and pepper into a small bowl. Take each cut up piece of feta cheese and roll into breadcrumb mixture, and then stuff cheese into chicken breast pocket, (approximately 2 pieces into each breast) Add salt and pepper to each side of chicken just before cooking.
Heat oil and garlic in frying pan, fry chicken on medium heat 3-4 minutes on each side or until brown on the outside and cheese is melted and chicken is completely cooked on the inside. To serve, slice chicken (london broil fashion) arrange on a plate sprinkle with crumbled feta cheese.