How to thicken a hot chocolate microwave recipe
I'm not familiar with psyllium husks or guar gum, but I do know cornstarch and xanthan gum. Cornstarch needs be heated to 203 degrees Fahrenheit to have a thickening effect, but xanthan gum doesn't. Since you're making it in the microwave, using cornstarch and maintaining that heat may be difficult. I've actually used xanthan gum to thicken hot chocolate before, and I usually use a pinch per cup of milk, but if you want something more puddinglike I might bump it up to 1/2 teaspoon and go from there. Be aware, though, that too much xanthan gum may cause gas or bloating.