In a large metal bowl, add eggs and sugar. Whisk until the color turns white-ish, and it becomes frothy.
Add melted butter into the egg mixture. Make sure the melted butter is at a lukewarm temperature, otherwise, it will cook the egg mixture when combining.
Sift the all-purpose flour and salt into the mixture. Mix until just combine. Overmixing it would cause a rubbery texture.
Add milk into the batter, 1/3 at a time. Mix until combine before pouring more.
Prepare another metal bowl. Run the batter through a sieve to ensure a smooth batter.
Cover the bowl with plastic wrap. Put in the fridge for at least 1 hour or best overnight.
Just 5 minutes before you are using the crepe batter, sift matcha, hojicha, and genmaicha powder respectively into three small bowls/ramekins. Add 1½ tbsp hot water into the matcha and hojicha powder. Add 1 tbsp hot water into the genmaicha powder. Mix until combined.
Prepare two empty mixing bowls. Divide the batter into three equal portions (mine was 310g each). Take 1/3 batter (~103g) out of bowl A and pour into Bowl B. Now you will have three bowls of batter - bowl A: 206g; bowl B: 413g; and bowl C: 310g.
Pour the genmaicha, hojicha, and matcha mixture into bowl A, B, and C respectively. Genmaicha would have the least batter because it is at the top of the cake. Hojicha would have the most batter because it creates a beautiful cake base.