Preheat the oven to 325°F and line an 8x8 baking pan with parchment paper.

Cut the vanilla bean in half lengthwise. Then use the knife to scrap out the seeds. Add the vanilla bean seeds to ¾ cup of the baker’s sugar and use your clean hands to work the vanilla seeds into the sugar. Set aside.

Now beat the room temperature egg whites, 2 tablespoons of baker’s sugar and 1 teaspoon of vanilla with a hand mixer or stand mixer until stiff peaks. Set aside.

Then beat the room temperature egg yolks with the vanilla sugar on medium speed for about 2 minutes, until light and pale in color.

Add the melted butter and beat for another minute until well blended.

Now add the flour and mix on low until the batter is smooth. The batter is very thick at this point.

Slowly add the milk on low, using about ¼ - ½ cup at a time until the batter is well mixed. It will be quite thin once all the milk has been added.

Gently whisk the egg whites into the batter in three additions. You don’t want to deflate the whites and will see some clumpy bits of egg whites floating at the top.

Pour the batter into the prepared pan and place in the preheated oven.

Bake for 40-65 minutes or until the top is golden brown and the cake just lightly jiggles when the side of the pan is gently shaken. The bake time can vary depending on your oven. Check the cake at 40 minutes and if necessary lightly tent with a piece of aluminum foil. Continue to check at 10 minute intervals until done.

Allow to cool completely before removing from the pan. Top with powdered sugar before serving, if desired.