Cream together the spread and sugar till light and fluffy. Beat in the eggs, one by one followed by 2 tbsp. of the flour. Sift together the remaining flour and baking powder and mix in, along with the pistachios. Place the teabag and food colouring in a bowl and add in 3-4 tbsp. hot water and allow to infuse. Discard the teabag and mix the green tea into the cake batter. Line 2 x 8inch round cake tins with baking paper and fill with the cake batter. Even out well and bake in the oven at 180°C for 20-25 minutes or until cooked. Remove from the oven and allow to cool down completely. Next, whip the double cream with the vanilla to soft peaks then add in the mascarpone and icing sugar and beat together till smooth. Cut the cakes in half diagonally and use the cream to fill the cakes, along with half of the berries. Finish off by decorating the top with the remaining berries, edible flowers and leaves.