Spray a 9x13-inch (23x33 cm) baking dish with nonstick cooking spray and set aside.
Make the almond cream by combining the almond flour, softened butter, sugar, almond extract, and beaten eggs in the bowl of a stand mixer. Mix until smooth. Scrape down the bowl, add the flour, and mix again. Set aside.
2¼ cups (216 g) almond flour, ¾ cup (170 g) unsalted butter, ¾ cup (150 g) granulated sugar, 1½ tsps (7 ml) almond extract, 3 large eggs, 3 tbsps (24 g) all-purpose flour
Preheat the oven to 350°F (177°C).
Make the bread pudding base. Whisk the beaten eggs, milk, heavy cream, melted butter, granulated sugar, brown sugar, cinnamon, vanilla extract, almond extract, and nutmeg in a large mixing bowl until the custard mixture is completely blended. This mixture is the foundation of the pudding’s texture, so whisk until no streaks remain.
6 large eggs, 2 cups (480 ml) whole milk, 1 cup (240 ml) heavy whipping cream, 6 tbsps (85 g) butter, ¼ cup (50 g) granulated sugar, ½ cup (110 g) light brown sugar, 1 tsp (3 g) ground cinnamon, 1 tsp (5 ml) vanilla extract, 1 tsp (5 ml) almond extract, ¼ tsp (0.5 g) ground nutmeg
Tear the bread into rough 2-inch (5 cm) pieces and spread half of it in the prepared baking dish.
1 lb (454 g) Italian country loaf
Pour half of the custard mixture over the bread so it fully absorbs into the pieces. This step allows the interior to bake creamy rather than dry.
Transfer the almond cream to a large pastry bag and cut a 1-inch (2.5 cm) opening. A large zip-top bag works as well. Pipe dollops of almond cream evenly over the soaked bread layer, creating pockets that will bake into a marzipan-like interior.
Add the remaining bread to the dish and pour the rest of the custard mixture evenly over the top.
Scatter the sliced almonds over the surface, pressing a few lightly into the bread so they adhere during baking.
½ cup (43 g) sliced almonds
Let the mixture rest for at least 10 minutes so the bread has time to absorb the custard before baking.
Cover the dish loosely with tented foil and bake for 45 to 50 minutes, removing the foil during the last 5 minutes. The center should be set and the top golden with a slight spring when touched.
Make the brown sugar glaze by melting the butter in a small saucepan over medium heat. Add the brown sugar and whisk until dissolved and lightly foamy. Whisk in the vanilla, then the heavy cream, until the sauce becomes smooth. Remove from the heat.
8 tbsps (113 g) butter, 3 tbsps (40 g) light brown sugar, 1½ tsps (7 ml) vanilla extract, 2 tbsps (30 ml) heavy whipping cream
Pour the warm glaze evenly over the baked bread pudding. Serve warm.