Prepare the Hot Cross Bun Dough:

1. Activate the Yeast: In a small bowl, combine the warm milk with 1 tablespoon of sugar. Sprinkle the yeast over the milk and stir until dissolved. Let the mixture sit for 5-10 minutes until it becomes frothy. If the yeast doesn’t froth, discard the mixture and start with new yeast.

2. Mix the Wet Ingredients: In a large bowl, combine the melted butter, remaining sugar, vanilla extract, and salt. Add the frothy yeast mixture to the bowl, followed by the egg. Mix everything together until smooth.

3. Add the Dry Ingredients: In a separate bowl, sift together the flour, cinnamon, nutmeg, and allspice. Gradually add the flour mixture to the wet ingredients, stirring to combine. If using orange and lemon zest, add them at this stage as well.

4. Knead the Dough: Turn the dough out onto a lightly floured surface and knead for about 8-10 minutes, until the dough becomes smooth and elastic. You can also use a stand mixer with a dough hook for this step.

5. Add the Fruit: Once the dough is smooth, fold in the currants or raisins, ensuring they are evenly distributed throughout the dough.

6. First Rise: Shape the dough into a ball and place it in a lightly greased bowl. Cover the bowl with a damp cloth and let it rise for 1 to 1 ½ hours, or until it has doubled in size.

Shape the Buns:

7. Preheat the Oven: Preheat your oven to 375°F (190°C) and grease a 9×13-inch baking dish or line it with parchment paper.

8. Shape the Dough into Buns: Once the dough has risen, punch it down to release the air. Divide the dough into 12 equal portions and shape each portion into a ball. Place the dough balls in the prepared baking dish, ensuring they are close together but not touching.

9. Second Rise: Cover the baking dish with a clean kitchen towel and allow the buns to rise for another 30-45 minutes, or until they have puffed up and are nearly touching each other.

Bake the Hot Cross Buns:

10. Bake the Buns: Bake the buns in the preheated oven for 18-20 minutes or until they are golden brown on top and cooked through. You can check for doneness by tapping the bottom of a bun; it should sound hollow.

Prepare the Cross and Glaze:

11. Make the Cross: While the buns are baking, make the cross by mixing the powdered sugar and water or milk until you have a smooth, thick icing. Transfer this mixture to a piping bag or a plastic sandwich bag with the tip cut off. Once the buns are out of the oven and slightly cooled, pipe a cross over each bun.

12. Glaze the Buns: For the glaze, combine the sugar and water in a small saucepan and heat it over medium heat until the sugar dissolves. Bring it to a boil and let it simmer for 1-2 minutes. Brush the glaze over the buns while they are still warm to give them a glossy finish.

Cool and Serve:

13. Let Cool: Allow the buns to cool slightly before serving. These buns are best enjoyed warm, but they’re also delicious at room temperature.

14. Cut and Serve: Once cooled to your desired temperature, cut the buns and serve them on their own or with butter, jam, or clotted cream for a truly indulgent treat.