Preheat the oven on 355 ºF/180 ºC.
In a stand-mixer bowl with a whisk-attachment (or large bowl with handheld mixer), whisk large egg yolks, large eggs and powdered sugar (optional) just until combined, then pause.
Heat up honey in a pot over medium-low heat until it starts to simmer, then continue to let it bubble and simmer for 2 minutes.
Turn the stand-mixer back on medium-high speed, then slowly pour the hot honey from the side of the bowl into the eggs with the machine running.
Keep whisking the eggs and honey mixture on medium-high speed until it becomes pale and thick, almost doubled in size.
Sift the cake flour right into the bowl, then whisk on low-speed until the flour is completely and smoothly incorporated.
Butter and flour the interior of the cake-pan (6" or no bigger than 7"), then dust off excess flour.
Pour the batter into the pan, then gently tap it a few times again to eliminate large air-bubbles.
Bake in the oven on the middle rack for 15 ~ 16 min.
Let the cake cool inside the pan on a cooling-rack for at least 30 min.