Leave the egg and butter out to become room temperature 30 minutes prior to making
Sift the dry ingredients together in a separate bowl.
Start to preheat the oven to 356°F(180°C)
Add the butter and sugar into a bowl and whisk until the mixture becomes white.
Add the beaten egg in 3-4 different times. And beat well every time egg added.
Fold the sifted flour into the batter and add half of the kuromame and chestnuts bits. *2
Pour the batter evenly into 6 muffin cups with an ice cream scoop, and topp with the remaining Kuromame and chestnuts bits.
Bake in the preheated oven for 30 minutes at 170℃ (340℉). *3
Notes
*1 A large sized egg weighs about 50g in Australia. *2 Be careful not overmix. You can add milk when you still see some flour left. *3 The oven temperature will drop when the door is opened. That's why to set the oven temperature to 356°F(180°C). After placing the muffin form in, set the temperature down to 340°F(170°C). *4 Kuromame can be replaced with choc chip, any nuts, or raisin etc.