Cut bread slices in half.
In saucepan, melt butter. Add brown sugar and corn syrup. Bring to boil, stirring frequently.
Pour into 8-inch square baking dish. Arrange bread slices over caramel mixture.
In small bowl, whisk eggs, half-and-half, vanilla extract, cinnamon and salt. Pour over bread slices. Cover with aluminum foil and refrigerate overnight.
Heat oven to 350° F.
Remove from refrigerator 30 minutes before baking and remove aluminum foil.
Bake 25-35 minutes, or until toothpick inserted into center comes out clean.
Sprinkle with powdered sugar, if desired; serve.