In a small heavy saucepan, melt butter with brown sugar and corn syrup over moderate heat, stirring until smooth

Pour into a 9x13 inch baking dish

Cut 6x 1-inch thick slices from the bread reserving ends for another use and cutting away crusts if desired

Arrange bread slices in one later in baking dish, squeezing them slightly to fit

In a bowl, whisk together eggs, half and half, vanilla, Grand Marnier, and salt until combined well and pour evenly over bread

Chill bread mixture, covered, between 8 hours and one day

Once ready, preheat oven to 350°F and bring bread mixture to room temperature

Bake bread mixture, uncovered, in middle of oven, until puffed and edges are pale golden, about 35 to 40 minutes

Serve hot with fresh berries of choice