Preheat the oven to 190 ºC and spray two 23 cm pie dishes with non-stick spray. Sift the dry ingredients together.
Rub in the butter and add the oil and eggs.
Mix until smooth and, using a spatula, spread thinly on the bottom and against the sides of the two 23 cm pie dishes.
Mix the cake flour and salt together and mix with a little water to form a smooth paste.
Heat the butter, milk, cinnamon stick and sugar together, stirring until the sugar has dissolved. Heat until just below boiling point and remove from the stove.
Beat the egg yolks into the flour paste and beat in a little of the hot milk mixture.
Beat in the remaining milk mixture and stir over low heat until thick and done.
Pour through a sieve if desired.
Beat the egg whites until soft peaks are formed and fold into the cooked milk mixture.
Pour into the prepared pie crusts and bake for about 20 minutes until lightly browned.
Sprinkle with cinnamon sugar and serve lukewarm.
Makes two tarts