To make the Speculoos Filling:

Cup of Yum
1. Mix the mascarpone with the speculoos spread in a small bowl until well combined.
2. Spread a sheet of baking paper on a small plate and form 12 small dollops of the mixture.
3. Freeze for 30 minutes.
4. Take the plate out and sprinkle it lightly with cornflour.
5. Form the small mounds into balls and put them back in the freezer.

To make the mochi dough:

1. In a microwave-safe bowl, mix the glutinous rice flour, sugar, cinnamon, and salt.
2. Gradually add the cold water, stirring constantly so as not to create lumps.
3. Cover the bowl with a lid or plastic wrap and place it in the microwave for 1 minute at maximum power.
4. Stir lightly with a spatula.
5. Cover and cook in the microwave for another 1 minute.
6. Stir again, cover and return to the microwave for 30 seconds. (Note: in my microwave, I had to add one more 30 seconds to get the mochi dough to the right consistency- so 3 minutes in all.)
7. Sprinkle a work surface with cornflour.
8. Place the still-hot dough on the work surface and sprinkle it with a thin layer of cornflour.
9. 2 Options: Form the dough into a sausage of about 30 centimeters (12 inches) in length then cut the dough into 40 gram (1 1/2 ounce) pieces. OR: Slide the dough between your thumb and forefinger (dust your hands well with cornflour), then pinch strongly and detach the piece of dough to form a small ball of about 40 grams (1 1/2 ounces).
10. With hands dusted with the cornflour, lightly squash the dough ball between your hands to form a 6-7 centimeter (2 1/2-2 3/4 inch) disc.
11. Place a very cold ball of the speculoos filling on the disc of mochi dough. Quickly gather the edges on top of the ball by pinching them together to seal.
12. Quickly roll the resulting ball between your hands to even it out and place it on a plate, seam side down.
13. Repeat to form the remaining mochi, then place them in the fridge to let them cool.
14. Take the mochi out of the refrigerator 30 minutes before eating to let them come to room temperature.