Combine brassicas in a bowl with the parsley. Toss with 1 table-spoon of the flour, to coat.
In a pot or a deep fryer, heat oil to 350°F. If using a pot, make sure the oil is 2 inches in depth, and the pot is deep enough for deep-frying — a candy thermometer is helpful to measure the oil tem-perature. While the oil is heating, make the batter. It’s important that the batter be the last component assembled before frying, to ensure a light, crisp tempura.
In a bowl, beat the egg and the yolk, add the ice water and mix thoroughly. Add flour in one shot. Using chopsticks or a small whisk, mash/chop at the batter, making sure to not over mix — do not stir. Over-mixing develops the glutens and results in a bread-like, doughy, finished product. The batter should be runny and lumpy, with visible bits of unmixed flour in the batter and around the edge of the bowl.
Add the batter to the brassicas and toss gently to coat. When the oil is ready, begin frying in small batches. Using chopsticks or a large ladle, scoop up some of the mix, and slide it slowly in to the hot oil. If you’re careful, the fritter/pancake will not break up much, however, should the tempura break up a bit, you can always repair it by pouring a little batter on and around the break. Fry for 2-3 minutes on one side, then flip, and fry for another 1-2 minutes. You’re aiming for a light golden colour and a crisp texture. Remove the tempura from the oil using chopsticks or a fine mesh strainer and transfer to a wire rack. Season the tempura with salt. Skim any bits of vegetable or batter from the oil with a fine mesh strainer before frying each batch. Continue to fry a few at a time — do not crowd the pot/fryer. This will ensure the oil stays hot and the tempura will not become greasy or soggy.
Pour tentsuyu into shallow bowls, with grated daikon and ginger on the side. Allow diners to mix desired quantities of daikon or ginger into the sauce, to taste.
Tentsuyu (tempura dipping sauce)
1 ½ cups dashi or vegetable stock
2 tablespoons light soy sauce
2 tablespoons mirin
salt & sugar to taste
Combine all ingredients in a small saucepot. Bring to a simmer, and turn off. Season to taste. Serve warm or at room temperature.