Prepare the Pumpkin Filling: In a large mixing bowl, combine the pumpkin puree, oat flour, Splenda, and cinnamon. Stir well until all the ingredients are fully incorporated. The mixture should become thick and dough-like, making it easy to form into small balls later on. If it feels too sticky, you can add a bit more oat flour (start with an additional tablespoon) until you reach the desired consistency.

Shape the Truffles: Once your filling mixture is ready, use a small spoon or a cookie scoop to portion out the dough. Roll each portion between your palms to form small balls about the size of a walnut. This should make about 20 truffles. Place the formed balls on a parchment-lined baking sheet or plate and refrigerate them for at least 30 minutes. Chilling helps the truffles firm up and makes them easier to coat with chocolate.

Melt the Chocolate: In the meantime, prepare the chocolate coating. Place the grated dark chocolate and 1 teaspoon of oil in a heatproof bowl. The oil helps the chocolate melt smoothly and gives it a glossy finish.

Double boiler method: Set the bowl over a saucepan with gently simmering water (make sure the water doesn't touch the bowl). Stir the chocolate constantly until it's completely melted and smooth.

Microwave method: You can also melt the chocolate in the microwave, but make sure to do it in short 15-20 second bursts, stirring between each one to avoid burning the chocolate.

Dip the Truffles in Chocolate: Once your truffles have chilled and the chocolate is melted, take the truffles out of the refrigerator. Using a fork or dipping tool, carefully dip each truffle into the melted chocolate, coating it entirely. Let the excess chocolate drip off before placing the truffles back onto the parchment-lined baking sheet.

Toppings: If you want to add toppings like chopped nuts or sea salt, sprinkle them on while the chocolate is still wet.

Chill the Truffles: After all the truffles are coated in chocolate, place them back in the refrigerator for another 15-20 minutes to allow the chocolate to fully set. Once the chocolate has hardened, your Pumpkin Truffles are ready to serve!

Serve and Store: Enjoy these truffles right away, or store them in an airtight container in the refrigerator. They will keep fresh for up to a week. You can also freeze them for longer storage—just thaw them for a few minutes before enjoying.