1.
To make the granita, place 150g sugar, vanilla pod and seeds, and 150ml water in a saucepan over medium heat. Stir to dissolve sugar, then bring to a simmer and cook for 8 minutes or until thickened. Cool completely, then discard vanilla pod.
2.
Place cooled sugar syrup, strawberries and 4 cups (1L) cold water in a blender and whiz until smooth. Strain through a sieve into a 1.5L (6-cup) container, freeze for 1 hour, then agitate mixture with a fork. Repeat every hour for 4 hours, then freeze overnight until completely frozen.
3.
The next day, brush brioche slices with egg and scatter with remaining 50g sugar. Heat a non-stick frypan over medium heat, spray with oil and, in batches, cook the brioche for 1-2 minutes each side or until caramelised. Serve with granita.