Grease 6 large individual ramekins
(about 300ml each) and heat oven to
180C/160C fan/gas 4. Bring the milk,
lemon zest and butter to the boil, then
turn off the heat. Beat the egg yolks with
100g of the sugar, then strain the hot milk
over the egg yolks, beating constantly.
Pour this custard into a jug.
Push the brioche into the ramekins so
they are half-full. Pour the custard equally
over the brioche, place the ramekins on
a baking tray, then bake for 20 mins.
Meanwhile, bubble the jam with the
blackberries for 6-8 mins in a shallow pan
until they start to soften, then turn off the
heat. When the brioche has a few mins
left in the oven, whisk the egg whites in
a very clean bowl until they form peaks.
Gradually add the remaining 100g sugar
and continue to whisk until peaky again.
When the brioche is golden and puffed
up, spoon over the blackberries, then
top with swirls of egg white. Scatter each
with a little more sugar, then bake for
15 mins until golden. Leave to cool
slightly before enjoying while still warm.