IMO - Best premix masala chai on the general market is Tao of Tea's 500 mile Cha
. Add fresh ginger to that and you have a reasonable facimile of masala cha I've been served by my Indian friends. Most american masala cha brands have too much pepper, and most of the recipes I've gotten from Indian friends don't have much pepper in them if at all but they all have fresh ginger...
How I prepare it is:
Place about a teaspoon/cup of mix into a pan ( I use a bit more )
add fresh thin cut ginger slices to taste
Boil the mix in water on high for at least 5 minutes
Turn down heat a bit to medium and
Immediately add half-and-half to taste
Bring the temp back up to just under boil ( you do not want to boil the milk)
Remove from stove and let cool a bit
Strain into drinking glasses
If your tounge is not numb afterwards you have done something wrong..
Two additional suggestions.
1) I forget where I got it, but I have a authentic roadside vendor masala cha serving set that is really cool. There is a wire basket with cha glasses, and a neat strainer thingy. I'll post a pic if I can find it.
2) Make your own, here's a great masala cha recipe web site!