Preheat the oven to 375 F/ 190 C/gas mark 5. You will need a medium size casserole dish approx. 6 cm deep.
Tear up the buns and place in your casserole dish (they should be nice and snug).
Mash the bananas using a fork. In another bowl whisk together the eggs and milk, combine with the bananas and stir well.
Pour the mixture over the bread, stir thoroughly and set aside for 5 minutes. Give another stir, sprinkle the wheatgerm (omit if you are using wholewheat buns), sugar, drizzle with the melted butter and bake for 30-35 minutes.
Use either white of brown soft buns or a combination of both. If you use white buns I recommend sprinkling a little wheat germ over the top to add more fibre to your dish.
I recommend using very ripe/overripe bananas because they are sweeter than firm, not quite ripe ones. As most of the sweetness comes from the bananas they need to be as sweet as possible. So overripe are best!
I also recommend mashing the bananas using a fork, not pureeing. You'll be able to better appreciate the sweet baked banana pieces tucked in between the bread chunks.
This french toast casserole is best served hot straight from the oven.
Depending on the depth of your casserole dish baking times may vary.