1. Remove green leaves from strawberries and dry them thoroughly.
2. Prepare your work surface by covering it with parchment paper and dusting generously with cornstarch or Mochiko flour. Also dust a plate or container for finished mochi.
3. In a medium microwave-safe bowl, mix Mochiko flour and sugar.
4. Add water, vinegar, and food coloring to the bowl. Whisk until smooth.
5. Cover the bowl with a microwave-safe plate or plastic wrap.
6. Microwave on high for 1 minute. Remove and stir well. Re-cover and microwave for another minute. Repeat this process, stirring after each minute, until the mixture has cooked for a total of 4 minutes and is thick, sticky, and translucent.
7. Allow the mochi dough to cool slightly until safe to handle. Dust your hands with cornstarch or Mochiko flour.
8. Scoop a portion of dough (about 2 tablespoons), flatten into a disk 3½–4 inches wide.
9. Place one strawberry upside down in the center of the mochi disk. Pinch and stretch the dough around the strawberry to seal completely.
10. Roll the mochi gently into a ball and place seam-side down on the prepared plate. Repeat with remaining dough and strawberries.
11. Store finished mochi at room temperature in an airtight container for up to 1 day.