Heat 1 to 1½ inches of oil in a large pot over medium-high heat until it reaches 350°F. Adjust the heat to keep the oil at 350°F. Set a paper-towel lined wire rack near the stove.
Whisk together white rice flour, salt, and baking soda in a medium or large mixing bowl.
In a small mixing bowl, whisk together egg yolk and seltzer water until smooth and fizzy. Pour the egg and water into the flour and mix gently with a fork until just combined. Don't over mix - It is okay if there are still some dry clumps, but just make sure to mix in the flour from the bottom of the bowl.
Dip asparagus into the batter, making sure to have batter all over the spear. Shake off any excess batter.
Working three at a time (more or less depending on the size of your pot), drop the asparagus in the oil (being careful not to burn yourself) and fry for 1-3 minutes, turning gently with a spoon until crispy and light golden. Use a slotted spoon to transfer each spear to the paper-towel lined wire rack. Repeat with remaining asparagus.
Serve sprinkled with matcha salt, togarashi, and ponzu dipping sauce.
Matcha Salt
Grind the salt and matcha together with a mortar and pestle until fine. That's it - it's so easy.
Ponzu Sauce
Whisk together all of the ingredients in a metal bowl until combined. Garnish with chives if you wish.
This nutritional information has been automatically calculated, and as such, may be incomplete or inaccurate. Please reference the specific ingredients you use for the most accurate nutritional information.