Preheat oven to 350 degrees. Grease bottom and sides of a 9 inch cake pan, 2×6 inch cake pans, a loaf pan, or a 6 cup bundt pan (that’s what I use). Line bottom of whatever flat bottomed pans with parchment paper. Flour any areas not covered with parchment paper. Set pans aside.

Using a food processor or a box grater, puree or finely grate cucumber. If using a food processor, you’re aiming for a chunky slush, not a liquid. If using a box grater, you want to grate the cucumber not shred it. There will be about 1 and ½ cups. Set aside.

Using a hand mixer or a stand mixer, beat butter and sugar until they become light and fluffy (about 3 minutes). Add in egg yolks and mix to combine. Then add in cucumber and again mix to combine. The dough will look chunky but it’s just fine. Add in lime zest, lime juice, salt, then sprinkle baking soda and baking powder over top. Mix to combine. Sprinkle flour over top and mix to combine. Set aside.

In a clean bowl whip egg whites into soft peaks. Fold egg whites into batter. Then poor batter into pan. NOTE, batter will rise in the oven. Occasionally (because of the difference in amounts of cucumber or sizes of eggs) I’ve had to remove a couple of tablespoons of batter if my bundt pan appears much more than ¾ full. This shouldn’t be a problem in a loaf pan, but makes for a hard to remove bundt.

Bake for 18-25 minutes if using 2 cake pans. 30-40 minutes for bread pans or bundt pans. Once cake is removed from the oven, allow to cool for 5-10 minutes before removing it from the pan. If making frosting (see recipe here, make that now). The recipe for frosting makes enough for a naked cake, you’ll need to double the frosting to completely cover the cake.

While cake cools, make your icing. Zest lime and set zest aside. Combine powdered sugar and 2 tablespoons lime juice, use a fork to mix together. Then add in corn syrup if using. Thin mixture with additional lime juice or water if needed. Remove cake from pan and then pour icing over top. Immediately sprinkle the zest over the cake before the icing starts to set.