I've been wanting to know how to make these (and what they were called for that matter) for ages. Usually they are filled with sesame paste. I made them with red bean paste. Don't ask why, it'll just be a long and confusing story that really has no point.
I'm not actually sure these are mochi. Wikipedia is telling me otherwise but I don't know where to find the real name for it. I've been wondering how to make these for a while but it's really hard to find a recipe when you don't know what it's called. This recipe on My Kitchen is the closest I've gotten. Yay for Flickr. Anyway, mochi may be another name for it, though the only fillings I've seen for it was black sesami paste and a peanut filling.
These are a relatively typical asian dessert. It has a mildly sweet flavor, but like they say, 'not too sweet.' They are mild, small bites, not a 500 calorie sugar bomb. The thing with asian desserts is they aim to be not too sweet.
So at the asian market the closest I could find was this can that was just called 'Red Bean'. But it had sugar and stuff in it so I figured it was, at least flavorwise, what I was looking for. I pureed it to make red bean paste. This is a looser version of what is often in moon cakes and other asian desserts.
2 cups glutinous rice flour
1/2 cup cornstarch
1 cup boiling water
1 tbsp vegetable oil
3 tbsp sweetened condensed milk
1 can sweetened red bean
Puree the can of red bean until it forms a smooth paste.
Mix the cornstarch and rice flour together in a large bowl.
Slowly pour the water over the dry ingredients while mixing.
Mix in oil and milk.
Knead until the dough comes together. To help keep the dough from sticking, keep your hands wet.
Shape into balls.
Press your thumb into the balls to form a dimple. Fill the dimple with red bean paste. Seal the dough around the red bean paste.
Roll in your hand to make a round ball.
Bring a pot of water to a boil.
Drop the balls into the water, only enough for one layer in the pot. Do multiple batches.
Once they float, they are done.