The very word tempura is supposed to come from the Latin name for Ember Days: the Quattor Tempura. The earliest Christian missionaries in Japan, in the late 16th century, were Spanish and Portuguese [Jesuits]. They brought with them, as Catholics, the commitment to abstain from meat and pray at these moments of the year. From this need one one hand, and from Japanese culinary tradition,s, on the other, was born this wonderful dish.
[Evelyn Birge Vitz, A Continual Feast]
NB: This dish takes a bit of prep work, so enlist a friend
chopped fresh vegetables (broccoli, onion, sweet potatoes, peppers, etc)
3/4 cup vegetable oil
1 egg yolk
1 cup ice water
1 cup flour
Beat egg yolk lightly. Add water, and mix quickly to combine. Fold in flour, and stir until roughly mixed.
Heat oil in sauce pan. Dip vegetables in batter and deep fry until golden brown. Serve with rice or noodles.