Lay pieces of challah bread on a cookie tray and bake for 5 minutes. Once the bread is done, take it out of the oven and set aside. Lower the heat to 325ºF.
Meanwhile in a large bowl, whisk the milk, heavy cream, sugar, vanilla sugar and egg.
Put 2 teaspoons of green tea powder in a small cup and add about 2 tablespoons of milk mixture. Mix well until green tea powder has formed a smooth paste. Add to the large bowl and stir well.
Put the pieces of bread in the bowl and toss gently until coated. Refrigerate for 30 minutes.
Spray 2 ramekins with cooking spray and add a couple of spoonfuls of bread mixture in each one. Add a thin layer of chocolate on top and add another layer of bread mixture. Finish by topping with what’s left of the chocolate and put the ramekins on a cookie tray.
Add about an inch of water to the cookie tray and bake for 40 minutes.
When the bread pudding is done, sprinkle remaining green tea powder on top and serve hot or cold.
This dark chocolate bread pudding will keep refrigerated for up to a week.