In a microwave-safe bowl, whisk together glutinous rice flour, granulated sugar, cornstarch, and salt until evenly mixed.

Gradually add whole milk and water to the dry mixture, stirring continuously to create a smooth batter.

Cover the bowl with vented plastic wrap and microwave for 1 minute on high.

Stir and return for two additional rounds of 1 minute each, stirring in between.

Allow the dough to cool for 2–3 minutes after microwaving.

Generously dust your work surface with potato starch or cornstarch to prevent sticking.

Transfer the warm mochi dough onto the dusted surface and dust the top lightly with more starch.

Divide the dough into 8–10 equal pieces and roll each piece into a smooth ball.

Let the mochi balls cool for about 15 minutes at room temperature.

Gently brush off any excess starch from the mochi balls and serve, optionally drizzling with sweetened condensed milk.