Step 1

To make the topping: Mix together the sugar and citric acid; set it aside.

Step 2

, Preheat the oven to 325°F. Butter the inside of a 9” x 5” loaf pan or 12" x 4" tea loaf pan and coat with about half the topping; reserve the other half for the top of the cake.

Step 3

, To make the cake: In a large bowl, beat together the sugar, butter, salt, baking powder, vanilla, Fiori di Sicilia, and zest. Beat until the mixture is thoroughly combined, then add the eggs one at a time, beating well after each addition.

Step 4

, Stir together the orange juice concentrate and lemon juice. Add about 1/3 of the flour to the batter, stirring to combine. Stir in about half the orange juice mixture, then another third of the flour, the remaining orange juice, and the remaining flour.

Step 5

, Spoon the batter into the prepared pan.

Step 6

, To bake the cake: Bake the 9” x 5” cake for 60 to 70 minutes or the tea loaf for 50 to 60 minutes, until a toothpick inserted into the center comes out free of crumbs.

Step 7

, Remove the cake from the oven, and let it cool in the pan for 10 minutes. Gently loosen the sides and turn it out onto a rack.

Step 8

, Rub the top of the warm cake all over with the remaining sugar mixture. Allow the cake to cool completely before slicing.

Step 9

, Store leftover cake, well wrapped, at room temperature for several days; freeze for up to 1 month.