Line an 8-inch/20-cm square pan with parchment, leaving the paper higher than the sides so the baked cake can be lifted out. Preheat the oven to 160°C/320°F.

Stir the honey and hot water together in a small bowl until completely smooth and fluid. Set the mixture aside while you prepare the egg foam.

Place the eggs and sugar in a large heatproof bowl and set it over warm water. Whisk until slightly warm, then beat with an electric mixer on high for about 5–7 minutes, until very pale, thick, and ribbon-like.

Add the diluted honey and mix on low speed just until incorporated. Avoid prolonged mixing because the egg foam is the cake's main source of lift.

Add the sifted bread flour in two or three additions, folding gently or mixing on low speed only until no dry flour remains. Stop as soon as the batter looks uniform to prevent knocking out the trapped air.

Pour the batter into the lined pan and tap the pan lightly on the counter to release large air bubbles. Smooth the surface only if necessary, since excessive handling can reduce the cake's volume.

Bake at 160°C/320°F for approximately 45–55 minutes, until the top is deeply golden and a skewer inserted in the center comes out clean. Remove the cake from the pan while it is still warm.

Wrap the warm cake tightly in plastic wrap or place it in an airtight container. Cool completely, then refrigerate if desired; trim the sides before cutting and serving.