In a saucepan, heat the milk with 20 grams of sugar (about 2 tablespoons) until the sugar has dissolved and the milk is starting to steam. Remove from heat and let it cool to lukewarm (100ºF - 110ºF).
Stir the active dry yeast into the lukewarm milk. Cover with a towel and let it bloom for 10 minutes, or until it is foamy.
In the bowl of a stand mixer, whisk together the flour, remaining sugar, salt, spices and orange zest.
With the mixer running on low, pour the milk and yeast, vanilla extract and add the eggs. Let the machine knead this mixture until a dough starts forming, then start adding the butter, one tablespoon at a time.
Once the butter is completely incorporated, knead the dough on medium-high for 3 minutes. After 3 minutes, turn the mixer off, cover the bowl with a kitchen towel and let it rest for 15 minutes.
Sprinkle the currants over the dough and knead again, on medium-high, for 3 more minutes.
Transfer the dough to a proofing container or a bowl covered with a towel. Let it rise for 1 to 2 hours, or until doubled in size.
Punch the inflated dough down and divide it into 15 equal parts. Form each part into a smooth ball and place them in a paper towel lined baking sheet, leaving 1 ½ to 2 inches in between them so they can expand. Cover with a towel and let them rise for 30 minutes to 1 hour, or until almost doubled in size.
Preheat oven to 375ºF with a rack in the middle.
Once the buns are done rising for the second time, make the flour paste by mixing the 75 grams of flour with the water. Add the water one tablespoon at a time, until you achieve a thick but runny consistency that can be piped.
Transfer the paste to a piping bag and cut the tip off with scissors. Pipe the crosses onto the buns.
Bake the buns for 20 to 25 minutes, or until golden brown on top. Remove from the heat and let them cool slightly.
While the buns are baking, heat the jam with water in the microwave for 15 seconds. Strain into a bowl and them brush on the warm buns.
Let the buns sit for 10-15 minutes so the glaze can set, then serve!