Stare them straight in the eye, never look away.
Also, agree with them. "Yeah, I am, and? What are, you, jealous?" Like what IS so wrong with your skin tone?
Plus it throws them off, because people expect ping pong.
"You're a snowflake"
"Oh yeah, well you're triggered"
Woopdee dee
"Snowflake? Called that right, an nice mushy one. Do you like snowflakes, because I can be a real real nice snowflake, make your snowflake dreams come true..."
I got flack (insults) when we moved to an Italian neighborhood when I was 8 which was not ideal for a half Puerto Rican in the 1970s. Funny thing was, to them, I LOOKED Italian, so they'd go from "Ey, Paisan" to "Go home, Spic" in a conversation, which shows how stupid racists are about their hatred.
I wasn't allowed to defend myself by my parents - they blamed me for it. In retrospect, that's what impacted me the most. The words from classmates are just words, they toughen you up. As the years went on, we all ended up friends anyways.
Anyways, not being allowed to defend myself, I ended up doing it for others when possible. Most had not seen my father since he was at work, so if they were trash talking other religions, races, countries, I would say, "Yo, father is Jewish" ... "Yo, my father is Black" .... it was funny seeing people chewing their tongues off trying to backpedal. Anyways, that's when I was a teen.
Then some folks in the country my father was born did some crap and I got flack for that. This was in HS, and like you, what got me was the worst of it came from this dude that was Black and another that was a PR. People who were my pals got all dicky. So that's when I started agreeing with them. Got right up their face and said, "Yeah, so what of it? Don't like it, do something, I'm right here, so do it anytime, like it now" ... "Go ahead, send me back" yadda yadda.
I guess it helps that my face tends to look pissed off and mean to start with, but whatever, people started backing off.
In HS I had one dude that stood by my side. Other than that, no one. My family said it was my fault, our relatives lived far, no one of my ethnicity to back me in the neighborhood.
Because my folks blamed me, I don't really get insulted when it's hurled at me, but it can piss me off royally when I see others catching it. That's when my tone changes from clowning around to more confrontational in defense of others.
Not saying my approach is for everyone. Bottom line, words are just words, and those people do not matter