In a large saucepan, combine the milk, sugar, cornstarch, and salt. Over a low-medium flame, begin to stir ever minute until first boil, about 8-9 minutes.
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 immedietly.
Once removed from the heat, 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.
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!