1-First Step: Prepare the watermelon juice Start by blending fresh watermelon until smooth, then strain it to get 240ml of juice. Ripe watermelon works best because it gives a stronger pink color and a naturally sweeter taste. If your watermelon is extra juicy, measure carefully so the liquid amount stays accurate. Too much juice can make the mochi too soft, while too little can make it firm. This step usually takes just a few minutes, so it is a good place to slow down and get the base right.

2-Second Step: Mix the dry ingredients In a mixing bowl, combine 200g glutinous rice flour, 65g granulated sugar, and 40g corn starch. Stir them together well so the sugar and starch spread evenly through the flour. This helps the final mochi cook smoothly without pockets of dry ingredients. If you need a starch swap for allergies, tapioca starch or arrowroot starch can work in place of corn starch. Keep a little extra starch nearby for dusting later.

3-Third Step: Add the wet ingredients and whisk Pour in the 240ml strained watermelon juice and add 1 1/2 tablespoons vegetable oil. Whisk until the batter looks smooth and lump-free. At this point, it should look like a pale pink liquid with a light, silky texture. If your watermelon is not very sweet, you can taste the juice before mixing and decide whether the sugar needs a small adjustment. This is a nice moment to think about your preferred sweetness level, especially if you are serving children or guests who like softer flavor.

4-Fourth Step: Cook the mixture on the stove Set a pan over medium heat and pour in the mochi mixture. Stir constantly for 5 to 8 minutes. You will see it begin to thicken, then slowly turn translucent as the starch cooks. That change in texture is your sign that the dough is coming together. Keep stirring so it does not stick to the pan or cook unevenly. If you prefer a softer finish, steaming is also an option, but the stovetop method gives good control and a quick result. The biggest clue that your mochi is ready is the translucent look. Once it changes from milky pink to glossy and semi-clear, it is usually time to move it to the mold.

5-Fifth Step: Shape it in a mold Line a 12cm x 12cm mold with cornstarch before pouring in the cooked mixture. This keeps the mochi from sticking and makes unmolding much easier later. Use a spatula or spoon to flatten the top so the surface is even. A smooth top helps the squares cut neatly after chilling. If you are working on a busy schedule, this step is fast and easy, which makes the recipe friendly for quick desserts after dinner.

6-Sixth Step: Chill until firm Place the mold in the fridge for 1 to 2 hours. This resting time lets the mochi set enough to slice without smearing. If you are in a hurry, the shorter end of the chill time may work, but waiting longer usually gives cleaner cuts. This is also a handy make-ahead dessert for party hosts, since you can chill it while you finish other dishes. For best results, keep it covered lightly so it does not dry out.

7-Final Step: Unmold, cut, and dust Once chilled, unmold the mochi onto a cornstarch-dusted surface. Dust the top with cornstarch, then cut it into 12 equal pieces. After that, coat all sides lightly with cornstarch so the squares do not stick to one another. You can dust your hands too, which makes handling much easier. Serve the pieces right away for the softest chew and brightest watermelon flavor.