Cut the French bread into cubes.
Make them about 1-inch size.
Let them sit out overnight if possible.
Stale bread works better for this recipe.
It soaks up the custard perfectly.
Whisk eggs in your large bowl.
Add milk, sugar, and vanilla extract.
Mix until everything combines well.
Add the cinnamon and melted butter.
Whisk again until smooth and creamy.
Put bread cubes in the bowl.
Pour custard mixture over the bread.
Press bread down gently with a spoon.
Let it soak for 30 minutes.
This step is very important. Don't skip it!
Preheat your oven to 350°F (175°C).
Grease your baking dish with butter.
Pour the soaked bread mixture in.
Spread it out evenly across the dish.
Add raisins on top if you like.
Bake for 45-50 minutes uncovered.
The top should turn golden brown.
A knife inserted should come out clean.
Let it cool for 10 minutes.
Dust with powdered sugar before serving.