2Butter the brioche slices on one side only then cut into large cubes by cutting each slice into quarters.
3Scatter brioche cubes, raspberries and blueberries into a large casserole dish and set aside.
4Whisk together yoghurt, milk, eggs and lemon zest in a large jug. Pour mixture over the brioche and leave to soak for 15-20 minutes.
5Sprinkle with demerara sugar then bake until a sharp knife inserted into the centre of the pudding comes out clean, about 35 minutes. Leave to cool for 10-15 minutes on a wire rack then serve with a dollop of yoghurt and a few fresh berries.