Mix the flour, salt, sugar and yeast in a bowl. Add the milk and eggs, knead for approx. 10 mins. using the dough hook on a food processor. Gradually add the butter and continue to knead for approx. 10 mins. Cover the dough and leave to rise for approx. 1 hr., then leave to rise in the fridge for approx. 8 hrs. or overnight.
Divide the dough into 8 portions, shape into balls, place in the prepared tin. Cover and leave to rise for a further 2 hrs. Whisk together the egg, water, salt and sugar, brush the brioche with the glaze.
Slide the brioche into the lower half of a cold oven. Bake at approx. 180 °C for approx. 50 mins. Remove from the oven, allow to cool slightly, remove from the tin and leave to cool completely on a rack.