In stand mixer fitted with a paddle attachment, add 1 cup flour, yeast, sugar, salt, lemon zest, cinnamon, cloves and nutmeg; mix well. In saucepan or microwave-safe dish, heat milk and water to 120-130°F. Add warm liquids and butter to flour mixture. Blend on low speed for 30 seconds; beat on medium speed for 4 minutes. Add egg; beat 1 minute.
Switch to dough hook attachment. Gradually stir in currants and enough remaining flour to make a firm dough. Knead until smooth and elastic, about 5 to 7 minutes.(NOTE: For hand mixing: following above steps, mix ingredients in large mixing bowl using a wooden spoon or dough whisk. Knead on floured surface until smooth and elastic.) Place dough in lightly oiled bowl and turn to grease top. Cover; let rise until indentation remains after poking dough with finger down to second knuckle, about 1 hour.
Prepare pans: Grease 2 cookie sheets; set aside.
Turn dough onto lightly floured surface; punch down to remove air bubbles. Divide into 3 equal parts. Divide each part into 6 pieces. Shape each piece into a smooth, round ball. Place on prepared pans, sides touching. Cover; let rise until indentation remains after touching.
Preheat oven to 375°F.
Brush risen buns with egg wash. Bake for 10 to 12 minutes. Remove from cookie sheets; cool on wire rack.
Make icing: In medium bowl, combine all icing ingredients; beat until smooth. Add more water/sugar to achieve desired consistency. Add icing to a zipper bag; seal shut. Snip the corner (not too big of a hole) and pipe icing into shape of a cross over top of each bun.