Preheat oven to 350 degrees and set racks in upper and lower thirds.
For the dough, combine the flour and baking powder, stirring well to mix. Whisk the eggs in a bowl, then whisk in all the remaining ingredients in order. Fold in the flour mixture.
Turn dough out on a floured surface and knead lightly to mix. Separate into 16 equal pieces. Roll each to an 8-inch rope, then into a circle. Place 5 or 6 on each pan.
Bake the taralli about 30 to 40 minutes, or until well puffed and deep golden. Cool on racks.
For the icing, combine all ingredients in a saucepan and heat gently until lukewarm. Brush over the tops of the cooled cookies. Sprinkle with multi-colored nonpareils, if desired.