Whip the egg whites in a bowl using a hand mixer.

Gradually add sugar in three portions while whipping to create meringue.

Sift almond flour, cake flour, and powdered sugar into the meringue and mix.

Transfer the mixture into a piping bag.

Spray water on the back of the dacquoise mold (optional for easier release).

Pipe the batter into the mold and smooth the surface with a scraper.

Dust powdered sugar twice over the sheets using a fine sieve.

Mix egg yolks, sugar, and vanilla extract in a bowl using a whisk.

Gradually add boiled milk while stirring to prevent the yolks from cooking.

Cook the mixture in a saucepan until thickened.

Cool the yolk cream to lukewarm, then whip in butter gradually.

Add soybean powder and mix evenly to complete the Injeolmi cream.

Fill the baked sheets with Injeolmi cream as desired.