Poke the chicken breasts all over with the tines of a fork. Place the chicken in a large resealable plastic bag.
Whisk together the olive oil, lemon zest, lemon juice, oregano, garlic clove, lemon pepper, and onion powder in a small bowl.
Pour the marinade over the chicken.
Refrigerate for 30 minutes.
Preheat oven to 400 degrees.
Fit a piece of parchment in a medium, rimmed sheet pan.
Remove the chicken from the marinade, and place on prepared sheet pan. Discard remaining marinade.
Bake for 20-25 minutes, or until chicken registers 165 degrees.
Serve on a plate with lemon slices, or over a bed of spinach with lemon wedges and a light vinaigrette.