In a large heavy-bottomed pot, combine the whole milk, heavy cream, brown sugar, cinnamon, nutmeg, allspice, and cardamom (if using). Whisk well to ensure the sugar and spices are fully dissolved.

Place the pot over medium heat. Bring the mixture to a gentle simmer, stirring occasionally to prevent scorching. Do not boil vigorously.

Once simmering, reduce the heat to low and stir in the vanilla extract, dried currants/raisins, and orange zest. Let it simmer very gently for 15-20 minutes, allowing the flavors to meld and the dried fruit to soften and plump up.

For a smoother soup, carefully pour the mixture through a fine-mesh sieve into a clean pot or heatproof bowl to remove the dried fruit and orange zest. You can discard the solids or add them back to the soup after straining if you prefer texture. Keep the soup warm over low heat.

If you desire a slightly thicker soup, in a small bowl, whisk together the cornstarch and cold water/milk until a smooth slurry forms. Gradually whisk the slurry into the warm soup. Continue to gently simmer for another 2-3 minutes, stirring constantly, until the soup has slightly thickened to your desired consistency.

While the soup is simmering, prepare the drizzle. In a small bowl, whisk together the powdered sugar and 2 tablespoons of milk/water until smooth. Add more milk/water, a tiny bit at a time, until you reach a thick, pourable consistency suitable for drizzling.

Ladle the warm Hot Cross Bun-Inspired Spiced Cream Soup into individual serving bowls. Drizzle the powdered sugar 'cross' mixture over the top of each serving. If using, sprinkle with hot cross bun croutons.

Serve immediately and enjoy this unique take on a classic flavor!