Mix the flour, baking powder, butter and sugar.
Add the vanilla and mix.
Add the milk and vinegar and beat the batter smooth.
Transfer onto the baking pan.
Bake at 100% for 2 minutes.
Turn container round and bake another 2 minutes.
Turn around again and bake 1 minute. Let stand for 5 minutes then turn cake out of the tin.
Key Ingredients: flour, vinegar, milk, vanilla essence, castor sugar, butter, baking powder