For the chinese cake dough
To prepare a gluten free Chinese cake start buttering a 23 cm round tin.
Mix together all the dry ingredients until combined. Set aside.
Heat together the butter and water in a pan until the butter has melted. Remove from the heat and stir in the milk.
Whisk in the egg, vinegar, oil and vanilla until combined.
Pour the wet ingredients for the Chinese cake into the dry ingredients and mix well until blended. Shape into a ball.
Take a large sheet of non-stick baking paper and sprinkle the paper with 1-2 tablespoons of sugar.
Place the dough on the paper and cover with another sheet of non-stick baking paper.
Pat the dough into a rectangle, then roll out to approximately 20 cm x 15 cm.
For the Chinese cake filling
Beat the butter until very soft, then beat in the remaining ingredients until blended.
Remove the top sheet of paper and spread the filling evenly across the dough, leaving 3 cm along one long end without any filling.
Starting along the long end, that has filling on it, use the sheet of baking paper to lift the edge of the dough and roll it up, forming a long cylinder.
Cut the cylinder into 8 pieces. Arrange the rolls next to each other in the tin, cut side up.
Cover with oiled cling film and leave to rise in a warm place for about 30 minutes, until nearly doubled in size.
Heat the oven to 180°C (160° fan) gas 4.
Bake for 20-25 minutes, until the tops are golden brown.
Cool in the tin for 5 minutes, then place on a wire rack to cool completely.
Sift over the Chinese cake a little icing sugar just before serving.