Place 16 mini silicone muffin cases on a baking sheet. Put the butter, 65 g (2½ oz) of the sugar, the flour, egg and ginger in a bowl and beat with a hand-held electric whisk until light and creamy. Divide among the cases.
Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 10–12 minutes until risen and just firm. Leave to cool in the cases for 2 minutes, then transfer to a wire rack to cool completely. Increase the oven temperature to 230°C (450°F), Gas Mark 8.
Heat the redcurrant jelly in a small saucepan with the measurement water until the jelly softens. Add the redcurrants and cook gently for 5 minutes to soften. Leave to cool.
Use a teaspoon to scoop out the centres of the cupcakes to make a cavity. Spoon the redcurrant mixture into the centres.
Whisk the egg whites in a thoroughly clean bowl until stiffly peaking. Gradually whisk in the remaining sugar, a dessertspoonful at a time and whisking well between each addition, until the mixture is stiff and glossy. Pile the meringue onto the cakes and swirl with a palette knife. Return to the baking sheet and bake for about 2 minutes, watching closely, until the meringue peaks are turning deep brown. Serve warm or cold decorated with small redcurrant sprigs.