Mixed Vegetable Tempura

Wash and cut the vegetables: For the asparagus, we only cut the hard bottom part. We slice the sweet potato, leave the mushrooms whole, and cut the red pepper into thick slices.
Combine all the dry ingredients for the tempura batter in a large mixing bowl.
Slowly pour in the sparkling water while mixing. Combine the batter gently, avoiding whisking. It’s fine if you can still see some dry flour pockets in the mixture, this will make the tempura extra crispy. You may not need to add all the sparkling water, so just add it slowly to get the batter to the right consistency.
You want the batter consistency to be light but thick enough to be able to coat the vegetables, similar to heavy cream.
Heat enough oil using a small pan for deep-frying.
When the oil is hot enough (I like using a tiny bit of batter to make sure it bubbles straight away), coat one type of vegetable (for example, all the mushrooms) and transfer them to the oil.
Deep-fry for a couple of minutes, until cooked through. Place the cooked vegetables on a paper towel to release the excess oil.
Repeat the process with the rest of the vegetables.
Make the dipping sauce by combining all the ingredients using a small serving bowl. You can also add some sesame seeds for texture.
Place all the tempura vegetables on a plate and serve them with the dipping sauce while still warm.