Heat the milk to around 95-100°F in a pot or in a small bowl in the microwave.
In the bowl of a stand mixer, whisk together the active dry yeast and the warmed milk and let sit till the yeast starts to bloom.
In a large bowl, zest the orange into the sugar and mix together with your fingertips or with the back of a spoon. On top of the sugar, add the flour, salt, butter, and allspice.
Make a little well (away from the sugar and salt) and place the egg in it. Now, you have everything ready for mixing when the yeast has bloomed.
Dump the flour mixture into the mixer bowl with the yeast. Mix on low speed with the paddle attachment until combined. Scrape down the sides with a stiff rubber spatula or bowl scraper.
Switch to the dough hook attachment and mix on medium speed until a rough window pane can be pulled.
Add the currants and mix in on low until well dispersed throughout the dough. Scrape the dough into a well-oiled bowl, cover it with plastic wrap, and allow it to be proofed for an hour in a warm place.
Fold the dough by grabbing one side, pulling it upwards out of the bowl, and then fold it over 1/3 of the dough. Rotate the bowl 180 degrees and repeat with the opposite side. Rotate a quarter turn and repeat the same folding technique. Rotate the bowl 180 degrees and make the final fold. You should have a nice tight square packet of dough.
Marvel at your skills. Cover with plastic wrap and allow to double. Mine took about an additional hour.
While the dough is finishing its bulk proof, grease a 9 x 13-inch baking dish with cooking spray or butter. I used butter because why not?!
When the dough has doubled and feels light and airy when touched, turn it out onto a lightly floured surface. It barely needs any flour!
Divide into 12 equal portions. You can eyeball this or weigh them. They should be about 87g each. Fold each of the 4 corners into the center flip over. Roll into a tight ball. Place each about equidistant apart in the prepared dish seam side down.
Cover with plastic wrap and return to the warm spot to double. This took about 30 minutes for mine. While the dough final proofs, make the cross top and the simple syrup.