Preheat your oven to 350°F (175°C). This ensures that your Berry Brioche Bread Pudding will bake evenly and develop a golden crust.
Take your day-old brioche bread and cut it into cubes about 1-inch in size. This helps them soak up the custard beautifully.
In a large mixing bowl, whisk together the eggs, brown sugar, vanilla extract, cinnamon, nutmeg, and salt until well combined. Slowly add in the half and half, whisking continuously until smooth and well mixed.
Place the brioche cubes into a greased baking dish. Pour the custard mixture over the bread, ensuring every piece is soaked. Let it sit for about 10 minutes to absorb.
Gently fold in the blueberries, raspberries, and butterscotch chips, distributing them evenly throughout the bread mixture.
Bake in the preheated oven for 45-50 minutes, or until the top is golden brown and a knife inserted in the center comes out clean.
Allow the Berry Brioche Bread Pudding to cool slightly before serving. Dust with powdered sugar for a lovely finish, and enjoy warm!