Combine lemon juice, olive oil, Dijon, garlic, rosemary, salt, pepper to make the marinade. Coat chicken in the marinade. Cover and refrigerate for at least an hour or overnight for best results.
Preheat oven, grease baking sheet, toss bread cubes with oil, melted butter, garlic, salt, black pepper, and Italian seasoning. Bake on sheet, flipping until golden brown (10-15 mins).