1 cup milk
1/2 cup white sugar
1 teaspoon vanilla extract
1/2 teaspoon sea salt
12 ounces brioche bread, cut into 3/4-inch cubes
1 pint blackberries, halved
4 ounces cream cheese, chilled and diced (optional)
aluminum foil (such as Reynolds Wrap®)
1 tablespoon unsalted butter, melted
Preheat an outdoor grill for medium-high heat, approximately 375 degrees F (190 degrees C).
Whisk milk, eggs, sugar, vanilla extract, and salt together in a large bowl. Fold in bread cubes, blackberries, and cream cheese. Set aside until liquid is absorbed, about 15 minutes.
Place a layer of heavy duty aluminum foil or 2 layers of regular aluminum foil on a flat surface. Brush aluminum foil with melted butter.
Arrange bread mixture in the center of the aluminum foil. Bring short ends together; fold over twice to seal. Bring sides in, leaving room for steam to form; fold over twice to seal.
Grill over indirect heat until bread pudding is puffed, liquid is absorbed, and edges are toasty, about 35 minutes.
Remove package from the grill; open carefully using tongs or mitts. Cool for 10 minutes.
For easier measuring, 12 ounces of brioche bread is about 4 cups cubed.