Prepare a baking sheet or cutting board with paper or a grate to transfer the fried mushrooms to.
Cut the brown bottom of the enoki mushroom off. Then slice the enoki mushrooms lengthwise into 2 to 3 slabs each, depending on the size of the mushrooms and desired thickness. The pieces should be approximately 1/2 inch wide, at the base.
In a deep pan or skillet, carefully heat about 1 1/2 inches of oil over medium-high heat until it reaches 350–375°F (180–190°C). You can test with a wooden chopstick - if bubbles form around it, the oil is ready.
Next, prepare the batter. In a large shallow bowl, combine all batter ingredients part from the sparkling water. Mix until well combined. Pour in the sparkling water, adding a bit more as needed to thin the batter to a “gloopy” pancake like batter consistency if needed.
Working one mushroom at a time, use tongs to coat the mushroom slices in the batter, and then fry. You can fry in batches if you have room. They require 2 to 3 minutes per side. The finished product should be golden and crisp.
Using tongs, carefully transfer to your prepared surface. Enjoy with your dipping sauce of choice.