- Trim stems from green beans. Chop broccoli and cauliflower into florets, about 1 cup each, and repurpose stems for another use.
- In a large bowl, whisk together flour, baking powder, a pinch of salt, seltzer, soy sauce and sesame oil. Set aside until ready to use.
- Heat oil to 325 degrees Fahrenheit. When oil is hot, use chop sticks or forks to toss vegetables a few at a time in the batter and then in the oil. Fry for 3-4 minutes each, stirring and flipping often. Cook in batches and remove to a paper towel lined plate when they are done.
- Sprinkle lightly with salt while still hot. Repeat with remaining batter and vegetables.
- Make ponzu sauce by stirring together ½ cup soy sauce and ½ cup mirin. Serve with fried vegetables.