I make Chai from scratch decently often. I use whole spices, give them a couple cracks with a pestle and add them to a pot of boiling water along with loose leaf black tea. I then let it continue to boil, or just cut the heat for a couple minutes, then add milk. I then bring it back to a boil, and wait for it to try to boil over. When it tries to boil over, you beat back the foam and take it off heat for a little. If you do that over and over, eventually, it won't foam up anymore because those proteins have denatured. That's when the tea gets that nice and silky texture. I'll also throw some honey in there.

I always make a big pot and have plenty of leftovers for cold chai.

I don't really measure anything, even though I should. I also change up ingredients. At a minimum, I always have green cardamom, ginger, and tea, but sometimes I also use black cardamom, cinnamon, cloves, aniseed, nutmeg, black pepper, or vanilla.