Preheat oven to 180°C. Line 24 muffin tins with cupcake papers.
Cream the butter with an electric mixer until smooth in a large bowl.
Gradually add the sugar and beat for 3 minutes until fluffy.
Add the eggs one at a time, beating well after each addition.
Sift the 2 flours and chai mixture into a separate bowl.
Add the dry ingredients in 3 parts, alternating with the milk and vanilla. Do not overmix!
Fill cupcake liners about 3/4 full with mixture and bake for 15 minutes until lightly golden brown.
Allow to cool in the tin for 15 minutes, then turn out onto a wire rack.