From Le Creuset:
I made a couple of modifications here, one out of necessity, the others out of preference.
First, the recipe calls for Japanese Milk Bread which I could not easily source, I subbed in croissant bread.
Second, the only spice is 1/2 teaspoon of cinnamon, I added 1/4 teaspoon each of nutmeg and cardamom.
Baked Blueberry French Toast with Mascarpone and Japanese Milk Bread
Cook Time
1 hour 30 minutes
Serving Size
6-8
INGREDIENTS
Unsalted butter, for the braiser
6 large eggs
3 cups whole milk
⅓ cup sugar
½ teaspoon ground cinnamon
½ teaspoon coarse salt
⅔ cup mascarpone
1 teaspoon vanilla bean paste
Zest of 1 lemon
10 slices Japanese milk bread, cut ½-inch thick
1½ cups fresh blueberries, divided
Confectioners’ sugar, for serving
INSTRUCTIONS
Lightly butter the Braiser.
In a bowl, whisk together the eggs, milk, sugar, cinnamon and salt until fully combined.
In a second small bowl, mix mascarpone, vanilla bean paste, and the zest of 1 lemon until smooth.
Dip each slice of Japanese milk bread into the custard so both sides are lightly coated. Arrange the dipped slices upright in slightly staggered rows across the braiser.
Tuck ¾ cup blueberries and small spoonfuls of the mascarpone mixture between the slices of bread. Pour the remaining custard evenly over the casserole. Cover and refrigerate for at least 30 minutes, or overnight.
When ready to bake, preheat the oven to 325°F.
Scatter the remaining blueberries across the top. Bake for 55–65 minutes, until the custard is set and the tops of the bread slices are lightly golden. Let rest for 10–15 minutes, then dust with confectioners’ sugar before serving.
Could try an Asian supermarket.