Preheat the oven to 350 degrees Fahrenheit (175 Celsius).
Add the raisins and rumchata to a small bowl and allow the raisins to soak in the rumchata for 20 minutes. After 20 minutes, strain the raisins and reserve the rumchatta for making the rumchata caramel sauce later.
Spray the baking dish liberally with baking spray and add the prepared panettone evenly into the bottom of the baking dish.
In a large bowl, thoroughly whisk together the eggs, milk, heavy cream, vanilla extract, melted butter, salt and nutmeg.
Top the panettone layer evenly with the rumchatta soaked raisins and sliced almonds. Pour the egg mixture evenly over the top of the contents in the baking dish pushing the panettone pieces gently into the egg mixture so the bread can soak up as much custard as much as possible.
Allow the bread pudding to rest for 20 minutes before baking.
Place the casserole dish on a parchment-lined baking sheet (optional), and bake in the preheated oven to 50-55 minutes, or until the custard is set and there is no runny egg mixture in the center. *Note - if the bread is browning too fast before the custard is set, cover the entire casserole dish with foil and continue baking until the custard is completely set.
Once fully set, remove the bread pudding to a wire rack to cool slightly before serving.
How to make the rumchata caramel sauce:
While the bread pudding bakes, combine the heavy cream, brown sugar, reserved rumchatta (from soaking the raisins), butter, salt, and nutmeg in a saucepan. Cook over medium heat, stirring frequently, until the sugar has thoroughly dissolved, and the mixture is fully incorporated.
Remove ½ cup of the hot cream mixture to a small bowl and whisk in the flour until a paste forms. Add the paste back into the saucepan and continue whisking (over medium heat) until the rumchatta caramel sauce thickens.
Use a fine mesh strainer to strain the thickened rumchata caramel sauce of any lumps of flour (if needed) to make a velvety smooth sauce.
Serve the panettone bread pudding in bowls with the rumchatta caramel sauce drizzled over the top of each serving.
Notes
Please be aware that the calorie count and nutritional information listed are a rough estimate for a serving of panettone bread pudding with rumchata caramel sauce.One serving = approximately ¾ cup. Store any leftovers in an airtight container in the refrigerator for up to 4 days.May be made ahead (before baking) and stored in the refrigerator (covered) overnight. Allow the bread pudding to sit at room temperature for 30 minutes before baking.May be frozen after baking. Store in airtight containers and freeze for up to 3 months.