Chiffon cakes are a special breed of cakes that are defined by their distinctive, airy crumb, achieved by the addition of baking powder (or other leavener) plus eggs. They are also on the moister side, thanks to those same eggs and also oil (instead of butter). Here the batter is mixed in the Thermomix, for the ultimate in ease. When baking, be sure to check with a cake tester before the recommended baking time, and allow the cake to sit in the turned-off oven as directed before removing.