Preheat your oven to 350º F, and line a baking sheet with parchment paper or a silicone baking mat.
Next, let’s cook some sweet potatoes.
You can do this one of two ways—in the microwave or in boiling water. If you use the microwave, poke a sweet potato with a fork a few times, put it on a plate, and microwave on high for 4 minutes. Carefully turn it over, and cook for another 2 minutes. Cut it in half lengthwise, and let it cool to the touch. Then, scrape out the sweet potato from the skin, and reserve 1 cup.
If you use boiling water, cut the potato into 1-inch pieces. Drop the potato pieces into the boiling water, and cook for 10-12 minutes until tender, and drain.
Add all of the ingredients except for the walnuts to a food processor and blend until everything is mixed well and the Batter is thick, but very smooth. Transfer your Batter to a mixing bowl, add the walnuts, and mix to incorporate.
Spoon your Batter by the tablespoon onto your lined baking sheet, making 12 equal size balls. Press down on each one slightly, so they are about ½ inch thick. Top with a piece of chopped walnut, if you’d like.
Bake for 25-30 minutes, until slightly firm to the touch. The centers will still be a bit soft, but will firm up as they cool.
Remove from the oven and let cool.