Wash your potatoes and remove the skin from the onion. Slice the onion in half. Grate the potatoes and the onion on a box grater on the larger holes.
Place the potatoes and onions in a clean dish towel or strong paper towels. Close the towel tightly and ring out excess water into the sink. They don’t need to be super dry. The starchy potato water will help with holding the cakes together when mixed with the flour.
Place the potatoes and onions in a bowl.
Add the flour, baking powder, and a pinch of salt and pepper to the bowl. Toss all together with your hands so that everything is well coated with the dry ingredients.
Preheat your GF grill.
Meanwhile, peel the apple and slice into 1/4” thick wedges, discarding the core.
Coat the grill plates with oil. An oil soaked paper towel held with tongs works well.
Form the potatoes into small, flat cakes approximately 2” in diameter. Place them on the hot grill. Coat the cakes with a little more oil. Close the lid and grill for 4 minutes, checking to make sure they are not burning.
Flip them over and grill for another 3 to 4 minutes until a deep golden brown and bubbling.
Remove the cakes to paper towels and sprinkle with a little salt. Continue until all of the cakes are cooked.
Place the apple slices on the hot grill and close the top.
Cook until light grill marks appear, approximately 3 to 4 minutes.
Serve the latkes and apple slices with some sour cream or yogurt on the side. You can eat them with your hands or a fork.