Using an electric mixer, beat butter and sugar until light and fluffy, add eggs one at a time, beating well after each,  add white chocolate and stir to combine, then add the green tea paste and stir until no streaks can be seen. Sift flour and baking powder over cake batter and fold in until combined. Line a 24 cup mini muffin tin with paper cases, then divide mixture among cases and bake at 180C for 12 to 15 minutes or until cakes spring back when lightly pressed. Cool completely.

Ganache

100 grams white eating chocolate

2 tablespoons of cream

Melt chopped white chocolate and cream in a medium bowl over a 1/2 full saucepan of simmering water, stirring until smooth. Careful not to overheat or your ganache will be grainy. Set aside stirring occasionally until thick enough to hold it's shape. Spoon onto centre of cupakes, decorate as desired.

Cakes keep up to 2 days in an airtight container.

If you want to make the fish toppers, use a fish chocolate or hard candy shaped mould sheet.

Fill cavities with melted white chocolate, once set pop out the fish and join two flat sides together or leave flat backed depending on whether you want your fish to stand up or lay down.  Apply gold leaf directly onto the chocolates one by one by using a small artists brush to lift and shape to gold onto the fish. You can save on gold leaf by making flat fish or by leaving every second fish plain white chocolate.

*matcha is available from some supermarkets and Japanese Grocery Stores.