Adapted from Epicurious
1/2 stick butter
1/2 cup brown sugar
1 tablespoon corn syrup
A half loaf of brioche or challah bread
3/4 cup half and half
1 teaspoon vanilla
2 teaspoons Grand Marnier
Pinch of salt
In a saucepan, melt the butter with brown sugar and corn syrup, stirring till smooth and sugar is dissolved. Pour into a 9 x 9 inch baking dish. Cut one inch slices of bread and arrange in one layer over caramel, cutting a slice if needed to cover completely.
Whisk together eggs, then add half and half, vanilla, Grand Marnier and a pinch of salt. Pour over bread, then cover and refrigerate overnight.
The next morning, bring French toast out of the fridge and allow to sit at room temperature about an hour. Preheat oven to 350º. Bake, covered, till puffed and golden about 25-30 minutes.
To serve, flip slices so caramel layer is on top. Serve with berries and real maple syrup if desire.
Easily doubles. Use a 9 x 13 dish and bake for 35-40 minutes.