Place the grapefruit juice, champagne, split vanilla pod and sugar in a pan and gently bring to boiling point, remove from heat, remove vanilla pod and add soaked gelatine leaves, stir to dissolve. Pour the mixture in the bottom of a glass serving dish and place in the fridge for about 3-4 hours or until it has set.
Prepare your almond sponge by preheating the oven to 200°C. Grease and line a baking tray, approx 38x25cm. Beat the sugar and 3 whole eggs with an electric mixer until pale and increased in volume, this will take about 5 minutes. In a separate bowl, beat egg whites to stiff peak stage and fold into the egg and sugar mixture. Sieve the almonds, flour and baking powder and gently fold into the eggs. Pour into prepared tin and bake for 12-15 minutes or until golden and a skewer comes out clean. Leave to cool in the tray.
Prepare the custard by placing the milk in a pan with the vanilla pod and bring to the boil. Mix the sugar, egg yolks and flour with an electric mixer until everything combined, thickened and has turned pale. Once the milk has boiled, remove the vanilla pod and pour onto the egg mixture in a steady stream whisking all the time. Return to the heat and stir with a wooden spoon over a moderate heat until the mixture thickens and reaches boiling point. Once gently boiling, continue stirring and cook for a further 2-3 minutes. Remove from heat and place in a bowl covered with a layer of cling film on the surface of the custard.
Once your sponge is completely cool, cut a circle of sponge to place on top of your set jelly. Depending on the size of your serving bowl, use an appropriately sized plate or base of a cake tin to help you cut a neat circle of sponge.
Place the cut sponge on top of your set jelly, cut the fresh strawberries in half and place them in a later on top of your almond sponge. Then spoon the cold custard on top of the strawberries and smooth to cover.
Prepare the mascarpone cream by beating the mascarpone to soften. Using an electric mixer, whip the cream, icing sugar and vanilla to peak stage and then fold in the softened mascarpone. Place this on top of your custard layer and spread to cover the top of your trifle. Finish by dotting raspberries all over the top of the mascarpone cream. Return to the fridge until ready to serve!
If you prefer use a selection of summer fruits or alternatively use whatever is your favourite and in season – all work well with the grapefruit and fruity rose champagne.
Time saving tip
Instead of making an almond sponge, substitute lightly crushed Amaretti biscuits to create a delicious almond layer between the zesty jelly and the vanilla custard.