Prepared using the 3 QT Square Le Creuset Casserole
Preheat oven to 375°F. Tear bread into large chunks, arrange in a single layer on a sheet pan, and bake in the oven as it preheats to dry. Bread should not brown, but just dry slightly.
Butter the inside of a stoneware baking dish. Whisk together eggs, yolks, brown sugar, salt, milk and vanilla in a large bowl. Arrange 1/3 of dried bread chunks in bottom of baking dish then top with spoonfuls of mascarpone and strawberry preserves. Repeat with two more layers of bread and topping each layer with remaining mascarpone and strawberry preserves. Pour custard mixture over the bread then lightly shake dish and gently press on bread so custard can absorb into bread. Cover and let rest for 15 minutes.
Bake covered for 30 minutes, remove lid and rotate dish, then continue baking uncovered for another 20 to 25 minutes or until bread pudding is puffed and golden and the custard is set.