In a large bowl, beat together the sugar and eggs until light and fluffy.
Slowly mix in the flour, baking powder, baking soda, and salt.
Whisk in the vanilla extract, milk, and butter until just combined to form a smooth batter. Cover and allow to rest for 1 hour.
Place an Indonesian cake mold or aebleskiver pan over medium heat.
Once heated, grease the cavities and decrease heat to medium-low/low.
Whisk the batter a couple of times to mix, then transfer to a pastry bag or plastic bag with the corner snipped off. Pipe the batter into the greased cavities, about 1/3-1/2 full depending on the size of the pan.
Cover the pan and cook for about a minute.
Top the cakes with desired toppings such as sprinkles, cookies, or coconut. Cover the pan again and cook to desired doneness, until the tops are just barely set and still a little shiny or up to 4 minutes to completely cook through. Adjust the heat between medium low-low as needed to cook the interior without burning the edges.
To make the Matcha Kue Cubit, whisk the matcha into the hot water until dissolved, then stir into the batter. Add more if needed to create the desired color.
Carefully remove the Kue Cubit with a hooked wooden stick or small spoons. Repeat with remaining batter, greasing as needed, and serve immediately.