Step 1: Prepare the Brioche. Cut the day-old brioche loaf into 1-inch to 1.5-inch cubes. If the brioche is fresh, spread the cubes on a baking sheet and toast in a 250°F (120°C) oven for 15-20 minutes until lightly golden and dried out. This prevents the pudding from becoming soggy.
Step 2: Make the Custard. In a large bowl, whisk together the eggs, whole milk, heavy cream, granulated sugar, light brown sugar, vanilla extract, ground cinnamon, ground nutmeg, and a pinch of salt until well combined and the sugars are dissolved. Ensure there are no lumps of spice.
Step 3: Assemble the Pudding. Generously grease a 9×13 inch baking dish. Arrange the dried brioche cubes evenly in the prepared dish. Pour the custard mixture evenly over the brioche cubes, making sure all the bread is well saturated. Gently press down the bread with a spatula to ensure it is fully submerged in the custard.
Step 4: Soak (Refrigerate). Cover the baking dish tightly with plastic wrap and refrigerate for at least 4 hours, or preferably overnight (up to 24 hours). This allows the brioche to fully absorb the custard, creating a tender and moist bread pudding.
Step 5: Bake. Preheat your oven to 375°F (190°C). Remove the bread pudding from the refrigerator about 30 minutes before baking to allow it to come closer to room temperature. Unwrap the dish and bake for 45-60 minutes, or until the top is golden brown, puffed, and the center is set. A knife inserted into the center should come out clean. If the top browns too quickly, lightly tent with aluminum foil.
Step 6: Serve. Let the French Toast Bread Pudding with Brioche cool for 10-15 minutes before serving. Dust with powdered sugar, drizzle with warm maple syrup, or serve with fresh berries and whipped cream. Enjoy this ultimate sweet breakfast!