Cookie Dough Daifuku Mochi

1. To prepare filling, beat butter and sugar together with an electric mixer for 2-3 minutes or until light and fluffy. Add flour and combine. Add milk, vanilla and salt and mix to incorporate. Stir in mini chocolate chips.
2. Scoop filling into 1″ balls (I used this small cookie scoop) and arrange on a parchment-lined tray. Refrigerate for 30 minutes while you prepare the mochi.
3. To make the mochi, whisk mochiko flour with sugar in a microwave-safe bowl. Add water and whisk until smooth and no lumps remain. Add a drop or two of food coloring, if desired, or leave white. If you want multiple colors, make a batch (or a half batch) of each color, one at a time, as the mochi is easiest to work with while it is still warm (so I do not recommend doubling this recipe in a single batch).
4. Loosely cover with plastic wrap and microwave for 1 minute on high. You should see some darker spots begin to appear. Stir well until uniformly paste-like in texture and even in color. Loosely cover again and microwave for another minute. Stir again. Continue to microwave and stir in 30 second intervals until mochi is evenly darkened in color and slightly transparent, and very stretchy and sticky. This will vary depending on your microwave, bowl, etc. I only needed one final 30 second burst for my mochi to be fully cooked. Note that smaller batches won't take quite as long to cook.
5. Dust a silpat (if you have one) or other non-stick surface with a layer of potato starch.
6. Dip a medium cookie scoop in water, then scoop out a 2-inch ball of warm mochi and place it on your starched surface, rolling to form a ball and coating evenly with starch.
7. Start to flatten the ball into a disk-shape (careful as the first few you make will still be quite warm). If you start to stick, just dust the mochi and your fingers with more starch.
8. Continue to flatten the disk, focusing mainly around the edges, until you have an approximately 3-inch circle. Set aside on a lightly-dusted surface. Repeat with remaining mochi.
9. Get your cookie dough balls out of the fridge. They should be firmer, but not solid.
10. Working with starch-dusted hands, lay one mochi disk in your palm, and place the cookie dough ball in the center. Bring opposite edges (at 12 and 6 oclock) together, pinching the mochi together to seal. Then bring the 3 and 9 oclock edges together, pinching to seal once again. You will now have 4 remaining 'points' sticking out; bring each one to the center and pinch together with its direct opposite, ultimately forming a dumpling-like ball.
11. Place pinched side down on starched surface and roll between your palms until perfectly round. Set on a lightly starched and parchment-lined tray. Repeat with remaining mochi.
12. Mochi will keep, refrigerated in an airtight container, for 1 to 2 days, though they are definitely better the first day. Let come to room temperature for a bit prior to serving.

*Mochiko flour is a sweet glutenous rice flour. Do not substitute regular rice flour here, it will not work. You can use other kinds of glutinous rice flour, such as Shiratamako, which supposedly creates a better textured mochi (though I haven't tried it personally, I plan to!)