Heat the rum in a small saucepan until hot. Pour the rum over the currant and let it sit for 2 hours. Drain before using.

Combine the milk, yeast, and 1/4 cup of the flour in a mixing bowl. Whisk to combine and let it sit for 10 minutes until it gets foamy. Whisk in the eggs, sugar, spices, salt, zest, and melted butter. Mix to combine.

With a dough hook attachment, add the 3/4 of the flour. Mix on medium speed until the dough starts to pull away from the sides of the bowl. Add more flour is needed. Knead for 8 minutes. Add the drained currants and mix on medium speed for another 2 minutes.

Transfer the dough to a lightly oiled bowl. Cover and place it in a warm area for 2 hours. After 2 hours, turn the dough out onto a lightly floured surface. Gently flatten and divide it into 16 equal pieces. Use a food scale if that helps.

Roll each piece into a ball and place it evenly spaced on a parchment or silpat lined baking sheet. Cover and let it rise for 20 minutes.

Mix together the water and flour. The mixture should be thick enough to hold it's shape and thin enough to pipe in a nice straight line. Put the mixture into a piping bag with a very small tip. Pipe the crosses onto the buns. Let it rise again in a warm area for another 20 minutes or until double in size.

Preheat the oven to 425F. Bake the buns for 15 minutes or until it's golden brown. Once done, let it cool on a rack.

Once the buns has cooled down, prepare the glaze by combing the sugar and water together in a small saucepan over medium heat. Stir until the sugar has dissolved. Cook the sugar until it reaches 225F.

Brush the glaze onto the buns and serve.