01 - Toast bread slices in a toaster or grill pan until golden and crisp.
02 - Cut the avocado in half, remove pit, and scoop the flesh into a small mixing bowl.
03 - Add lemon juice, olive oil, salt, and pepper to the avocado. Mash with a fork until mostly smooth, retaining some texture.
04 - Spread the mashed avocado evenly over the toasted bread slices.
05 - Sprinkle crumbled feta cheese on top of the avocado layer.
06 - Garnish with chili flakes and, if desired, fresh chives or parsley. Serve immediately.