Put everything in a medium pot placed over medium heat. Stir constantly until the sugars have dissolved. This should take less than a minute. You don’t want to reduce or thicken the sauce; it’s already very concentrated and further reduction will result in a much lower yield than intended which leads to over-seasoned Pad Thai.
To keep the sauce from being overly reduced, chop your palm sugar very finely and do not use high heat.
Once the sugar is dissolved, remove the sauce from heat; allow to cool. Store in a glass jar and refrigerate or freeze.
Recipe by SheSimmers at https://shesimmers.com/2011/11/pad-thai-recipe-part-four-pad-thai.html