Whisk together the eggs, milk, cream, vanilla, sugar and cinnamon in a medium bowl until combined. Set aside.
Grease a 9 x 13 inch / 23 x 33cm casserole dish or oven proof pan with melted butter or cooking spray.
Slice the croissants in half with a sharp bread knife then place the bottoms in a casserole dish. Pour over half of the custard.
Mix together 4 tablespoons sugar with 2 teaspoons cinnamon and sprinkle half of the cinnamon sugar over the croissants.
Place the tops of the croissants on top and pour over the remaining custard.
Press the croissants down into the custard to allow them to soak up as much of it as possible.
Sprinkle over the remaining cinnamon sugar. Cover and allow to rest for 20 minutes while you preheat the oven.
Preheat the oven to 180°C/350°F.
Uncover and place in the oven. Allow to bake for 15-20 minutes until golden brown on top.
Remove the baked French toast casserole from the oven and allow to cool for 10 minutes then scatter over the almonds and berries and dust over some powdered sugar (optional).