Add the maple syrup, water, and ginger slices to a small saucepan. Heat over medium heat until it comes to a boil. Once boiling, turn off the heat and let the ginger infuse the syrup for at least 30 minutes.
In the meantime, prepare the pumpkin juice by blending the pumpkin purée with the water. Set aside.
Discard the ginger slices from the syrup and divide the syrup between two glasses (about 3 tbsp per glass). Pour about 1/4 cup of the pumpkin juice into each glass and stir to combine.
Finish by pouring about 1/2 cup of cold sparkling water into each glass and serve immediately! If you want to top your ginger pumpkin fizz with whipped cream, prepare your cream before adding the sparkling water to the glasses (so you don't lose the bubbles in the meantime).
Aquafaba Whipped Cream (optional)
Whip the aquafaba using an electric mixer for about 5 minutes, or until soft peaks form. Next, add the powdered sugar, vanilla extract, and other extracts if using. Beat for another 3-5 minutes, or until stiff peaks form. Add a dollop of whipped cream on top of each glass and top with your favorite caramel sauce and sprinkles! Enjoy immediately!