Preheat the oven to 180°C.
Butter a baking dish (approx. 26 x 19 centimetres).
Combine the milk, eggs and vanilla in a bowl.
Mix apples, sugar, cinnamon, lemon juice and rum in separate bowl.
This bread pudding has 3 brioche layers with apples in between. You need 4 slices of the brioche for each layer if you are using a dish with the above dimensions.
Dip each brioche slice in milk and lay them next to each other at the bottom of the dish. You will most likely need to tear some brioche slices apart to make them cover the whole bottom.
Spread half of the apples over the first layer.
Lay another 4 brioche slices dipped in milk over the apples.
Spread the rest of the apples over the second brioche layer. Pour all juices from the apple mix in too, they are full of flavour.
Cover apples with remaining 4 pieces of brioche dipped in milk.
Lay slices/nobs of butter over the final layer and bake on 180°C for approximately 40 minutes.