Preheat the oven to 180C/360F. Grease a donut tin.
Mix the dry ingredients together in a mixing bowl. Add the wet ingredients and stir to combine.
Add the currants and zests.
Pour the mixture evenly into 12 donuts. A mini muffin tin or cake pop tin can be used instead but the cooking times will vary.
Make up and use the cross paste on the donuts before baking.
Bake for 13-15 minutes.
Immediately remove the warm donuts from the tray and roll in the sugar spice mix.
Eat warm or cooled.