Using heavy-duty aluminum foil, make a "breastplate" for the chicken. Fold a length of aluminum foil into a triangle, then press it to match the shape of the chicken breast. Remove the triangle, gently brush the inside with oil (the side that will touch the chicken), and set it aside.
Sprinkle the 1 Tablespoon of lemon-pepper seasoning over the surface of the chicken.
When the microwave is done, carefully remove the onion and apple from the hot water (use tongs), and place them inside the cavity of the chicken.
Cook the chicken, uncovered, on 450 degrees for 20 minutes.
After 20 minutes, remove the chicken from the oven, place the aluminum foil triangle over the chicken breast and insert a probe-style meat thermometer.
Turn the oven down to 350 degrees and return the chicken to the oven. (Do not wait for the oven to cool down to 350 degrees.)
Cook the chicken until the internal temperature of the breast reaches 165 degrees F. (Total cooking time should be approximately 20-25 minutes per pound.)