Add to large bowl a cup of ice cold water. Break the egg to the bowl and whisk it to a light foam.
Add the flours and cornstarch, I put the quantities measured with my eyes, not very strict.
Mix them together lightly, keep some lumps, they are needed in the tempura batter. The consistency of the batter should be similar to the pancake batter., so adjust with some cold water or flour if needed.
On a separate place spread a few tablespoons wheat flour.
Dredge the pumpkin flowers through this flour, then into the batter.
Heat the vegetable oil in a wok over high heat until very hot. Test the temperature of the oil with a few drops of batter, if they rise immediately to the surface of the oil, it is hot enough.
Fry the battered flowers in this hot oil a few minutes, turning once, until golden and place them after frying on a dripper or on paper kitchen towels.