Peel and grate the potatoes, apples, and onion. Put the grated ingredients in a large bowl, then add the flour, salt, baking powder, and black pepper. Mix until the flour is absorbed.
Put the Forager Project Sour Cream in a small bowl. Stir in the cinnamon and syrup. Refrigerate until ready to use.
Heat a non-stick pan over medium heat and add enough oil for frying (about ¼ inch). Scoop out heaping spoonfuls of the apple-potato batter and place in the pan (4 - 5 latkes at one time depending on the size of your pan). Flatten carefully with a spatula. Cook for 4-5 minutes until the latkes are browned; then flip and cook for another 2-3 minutes. Place on a paper towel-lined plate to absorb excess oil.
To serve, top the latkes with cinnamon sour cream.