In a bowl, combine the flour, brown sugar, baking powder, salt, and cinnamon and stir to combine.
For a smooth batter without sweet potato chunks, add the milk, mashed sweet potato, egg, and melted butter in a blender jar. Blend for 30 seconds until smooth. Otherwise, mix these ingredients in a bowl, using a fork to mash up the sweet potato until there are few to no lumps left.
Pour the wet ingredients into the dry ingredients bowl and mix until they're combined. Stop when there's no visible flour.
Cook the pancakes
Heat a non-stick pan over medium heat. Once hot, grease it with oil or butter. Immediately pour ¼ cup of batter per pancake. Cook the first side for 2 minutes. When the edges begin to look defined and bubbles form, flip them over and cook the other side for 2 more minutes. Don't press them down with a spatula; just let them fully cook.
Remove the pancakes from the pan and cook the rest. Serve them warm with your favorite syrup and toppings.
Storage
Refrigerate cooled pancakes in an airtight container or zip bag for up to 3 days or freeze them for up to 3 months. Reheat them in the microwave, in 30-second increments, or toast them.
Notes
Use a leftover cooked baked sweet potato for this recipe or cook a sweet potato in the microwave quickly. Open it in half, let it cool as much as you can, then use it to make this recipe. Click here to see how to cook it in the microwave and here for the air fryer.