Grate fresh old ginger root finely using a microplane, then squeeze the pulp through a fine-mesh strainer or cheesecloth into two heatproof ramekins or small bowls, putting 18.8 ml of juice into each bowl. Mix thoroughly before setting aside.

In a small saucepan, combine the whole milk, sugar, and milk powder (if using). Whisk over medium heat until the sugar dissolves completely and the milk reaches between 66 °C and 68 °C (65 °C–68 °C).

Remove the milk from heat. Quickly stir the ginger juice in the first bowl, hold the milk pot about 6 inches above the bowl, and pour half the hot milk straight into the center in one decisive stream without stirring afterwards. Repeat for the second bowl.

Immediately cover each ramekin with a small saucer or plastic wrap and let sit undisturbed at room temperature for 10 minutes until set.

Gently test the surface by placing a teaspoon flat on top of the pudding. If it holds the spoon without sinking, it is perfectly curdled. Serve warm.