Put the eggs and sugar in the bowl of a stand mixer fitted with the whisk. Beat on high for 6 to 8 minutes, until the mixture is pale, very frothy, and thick like custard.

Heat the oven to 315°F. Grease an 8×8-inch metal pan and line it with parchment paper, leaving the paper at least 1 inch above the rim.

Stir the honey, warm water, vanilla extract, and salt together in a small bowl.

With the mixer on low, blend the honey mixture into the eggs. Then add the cake flour gradually and stop mixing as soon as it disappears.

Pour the batter into the prepared pan and tap the pan on the counter to release large bubbles. Bake on the center rack for about 45 minutes, until the top is deep brown and puffed.

While the cake is still warm, lift it out by the parchment and peel the paper away. Wrap the cake tightly in plastic wrap and let it cool to room temperature while wrapped.

Once cooled, trim the browned edges, cut the cake in half to make two loaves, and slice each loaf into 1/2- to 1-inch pieces.