Before you start dipping the vegetables into your batter, make sure that they are all peeled and sliced into thin pieces.
Lightly coat your vegetable pieces in flour. (This step is optional, but it can help the batter stick to your veg better.)
Pour oil into a large wok or saucepan until it is one third full, and heat up over a medium-high heat.
Dip vegetables into the batter one at a time to lightly coat, starting with the root vegetables (any veg that is grown underground).
Gently shake off any excess batter, as too much batter will make your tempura too crispy on the outside and too mushy on the inside.
Add your veggie slices to the saucepan a few pieces at a time and begin deep frying. Don’t add too many pieces as this will drop the temperature of the oil.
Fry root vegetables for 3-4mins and non-root vegetables for 1-2mins, or until the batter is crispy and golden. Turn each piece about halfway to cook both sides.
Your shiso leaves will fry very fast, so sprinkle a little flour onto the back of the leaves and dip only the back into the batter. Deep fry for 15 seconds.
Transfer your tempura veg onto a cooling rack or plate lined up with paper towels to remove any excess oil.
Serve immediately with dipping sauce or as a dish with rice or noodles, and enjoy.