Butter a 9"x13” baking dish. Tear bread into ½” cubes (use half of the loaf) and set in bottom of baking dish. Layer cream cheese over the bread. Top with blackberries and remaining bread. (I added extra blackberries on top of this.) In a large bowl, mix together eggs, milk and syrup. Pour mixture over bread. Use a spoon or spatula to press down bread into mixture.
Cover pan with foil and refrigerate for 8 hours or overnight. Before cooking, set pan on counter for 30 minutes. Preheat oven to 350°F. Bake, covered, for 45 minutes. Uncover and bake for about 25 more minutes, or until top is golden brown and egg mixture is set.