Place bread cubes in a greased 13x9-in. baking dish; sprinkle with cranberries and walnuts. Whisk together next 11 ingredients until blended; pour over bread. Refrigerate, covered, overnight.
Preheat oven to 350°. Remove casserole from refrigerator while oven heats. Bake, uncovered, until puffed and golden, and a knife inserted in the center comes out clean, 30-35 minutes. Let stand 5-10 minutes before serving. Serve with syrup.
Editor's Note
To toast nuts, bake in a shallow pan in a 350° oven for 5-10 minutes or cook in a skillet over low heat until lightly browned, stirring occasionally.
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