Method

1. In a medium saucepan, whisk together sugar, cornstarch, salt, milk, and egg yolks (if you're using a powdered flavouring, mix this in now too).
2. Cook this mixture over medium-low heat. Whisk occasionally, about every minute or two, until it starts bubbling throughout, which should take about 7-8 minutes.
3. Once it begins to bubble, continue cooking for an additional 1-2 minutes, whisking once or twice, but gently to maintain the binding properties. The pudding will be thickened but still pourable at this stage and will thicken further as it cools.
4. Remove the saucepan from the heat. If you're using a liquid flavouring, e.g., vanilla extract, whisk it in now.
5. If you notice lumps and wish to remove them, place a fine mesh strainer over a large heatproof bowl and pour the mixture through it. If there are no lumps, you can skip this step.
6. Transfer the pudding into individual serving bowls or containers. Allow to cool until lukewarm, then cover with plastic wrap and refrigerate for several hours or until fully chilled.