Lightly coat a griddle or skillet with cooking spray and heat over medium heat.
Peel, core, and thinly slice apple into rings.
In a large mixing bowl, combine pancake mix, cinnamon, egg, canola oil, and milk. Stir until the ingredients are evenly moist. (Small lumps are ok! Over-mixing makes pancakes tough.)
For each pancake, place apple ring on griddle and pour about 1/4 cup batter over apple ring, starting in the center and covering the apple.
Cook until bubbles appear. Turn and cook other side until lightly brown.
To test the griddle to see if it is hot, sprinkle it with a few drops of water. When the drops sizzle and dance, you are ready to cook! The easiest way to pour the batter onto the hot griddle is to use a 1/4 cup measuring cup for each pancake. If the first pancake is too brown, lower the heat.