Prepare Your Hot Cross Buns: Start by cutting your Hot Cross Buns into generous 1-inch cubes. Arrange the cubes in a single, slightly overlapping layer in your prepared baking dish.

Make the Custard Base: In a large bowl, whisk together 4 large whole eggs and 2 large egg yolks with 3/4 cup granulated sugar until pale and well combined. Slowly whisk in 2 cups full-fat milk, 1 cup heavy cream, 2 teaspoons vanilla extract, and if desired, 1/2 teaspoon ground cinnamon and a pinch of freshly grated nutmeg. Whisk until fully incorporated and smooth.

Soak the Buns: Carefully pour the prepared custard base evenly over the Hot Cross Bun cubes in the baking dish. Gently press down on the buns to ensure all the bread pieces are fully submerged. Allow the pudding to soak at room temperature for at least 30 minutes, or refrigerate for 2-4 hours, or overnight.

Preheat Oven & Prepare for Baking: Preheat your oven to 350°F (175°C). Place your baking dish inside a larger roasting pan and pour hot water into the larger pan until it comes halfway up the sides of your bread pudding dish.

Bake the Pudding: Carefully transfer the roasting pan with the bread pudding to the preheated oven. Bake for 45-60 minutes, or until the top is golden brown and the center is mostly set with a slight jiggle remaining.

Cool & Serve: Once baked, carefully remove the bread pudding from the water bath and let it cool slightly on a wire rack for about 10-15 minutes before serving.