Preheat the oven to 160 degrees Celsius.

Grate the zest from the limes.

Separate the egg whites and yolks into separate bowls.

In a bowl, mix the lime zest with the egg yolks.

Add a pinch of ground cinnamon to the yolk mixture and stir.

In a separate bowl, whip the egg whites with a pinch of salt until they become foamy.

Gradually add the sugar to the egg whites while continuing to beat until you achieve a soft meringue.

Gently fold the egg yolk mixture into the meringue.

Sift the cake flour over the combined mixture.

Gently fold the flour into the batter until just combined.

Transfer the batter to a pastry bag fitted with a large tip.

Pipe flat, round cakes onto greased parchment paper.

Sprinkle the cakes with sugar and cinnamon, if desired.

Bake in the preheated oven for 10 to 15 minutes, or until the edges are golden brown.

Remove from the oven and place the cakes on a cooling rack.

Let cool slightly before serving.