Whisk the cornstarch. In a small bowl, whisk together the cornstarch and ¼ cup of the milk of your choice. Mix until no lumps remain. In a large saucepan, combine the remaining milk, sugar, cornstarch slurry, and salt.
Cook the pudding. Over a low-medium flame, stir almost constantly until first boil, about 9-10 minutes.
Finish cooking. After first boil, continue to stir for an additional 2-3 minutes or until desired thickness is achieved. Make sure to not burn the pudding on the bottom of the saucepan. If you notice brown flecks, the pudding is burning and remove from heat immediately.
Cool the pudding. When pudding has reached the thickness you like, remove the pudding from the heat. Now, add in your vanilla extract and other flavorings if using. Let cool on the countertop for 10 minutes, making sure to stir so as a crust does not form.
Transfer to dishes. Carefully transfer the pudding to the dishes of your choice to serve in. Let them cool on the countertop for 10 more minutes. Serve or chill.
Chill (optional). Place a bit of cling film on the top of the pudding before placing in the fridge to chill completely, about 3 hours. This can be saved in the fridge for up to 4 days. Enjoy!
