Preheat the oven to 180c / 350f and grease a 9×13-inch casserole pan with butter.
Arrange the bread slices in a single layer on a large baking sheet. Toast in the oven for 9-10 minutes or until lightly brown.
In a mixing bowl, whisk together sugar and 1 teaspoon of cinnamon.
In another mixing bowl, whisk together evaporated milk, milk, eggs, maple syrup, vanilla, lemon zest, salt, and the remaining ¼ teaspoon cinnamon.
Arrange the bread slices into the casserole pan.
Now, pour the custard mixture evenly over the top of the bread and then sprinkle on the cinnamon-sugar mixture.
Cover the pan with plastic wrap and put in the fridge for at least 4 hours or overnight.
When ready to bake: Preheat the oven to 180c / 350f. Bake in the oven for 30-40 minutes or until golden.
Remove from the oven and allow to cool. top with raspberry and serve warm.
Notes
I suggest you opt for a day-old bread since it absorbs the caster better than the new bread. You can also use whole wheat, gluten-free or sourdough bread.
The trick is to dry out the bread a little so it absorbs the liquids better. So, I start by toasting the bread in the oven for 10 minutes or so while preparing the custard.