1. Preheat the oven to 160°C. For the base, place the digestive biscuits in the Braun Multiquick 5’s hand blender compact kitchen machine with melted butter and pulse on a medium setting to combine. Press the mixture into the base of a 20cm round tart mould. Chill in the refrigerator for one hour to firm up. Rinse the appliance.
2. Place the filling ingredients except the egg whites in the Braun Multiquick 5’s hand blender compact kitchen machine and mix on a medium speed until smooth.
3. Beat the egg whites in the beaker using the Braun Multiquick 5’s hand blender whisk accessory, until stiff peaks form, then fold into the filling mixture using a wooden spoon. Pour the mixture over the base and bake in the pre-heated oven for 50-60 minutes until golden. Leave to rest for at least 30 minutes before slicing.
4. Clean the Braun Multiquick 5’s hand blender compact kitchen machine. For the coulis, put the strawberries, raspberries, sugar and lemon juice in the accessory and mix to form a purée. Pass the purée through a sieve and chill for 3 hours until ready to serve.