Thanks to HelloFresh for sponsoring this video! For 16 free meals with HelloFresh across 7 boxes AND 3 free gifts, use code ADAMRAGUSEA16: https://bit.ly/3H8Rbgh

My old video about anthocyanins (which make onions pink):    • Why food is blue (or usually isn't)  

My two favorite methods for pink pickled onions, based on the experiments in this video:

FAST: Slice a red onion into thin wedges from tip to root. Dump them in boiling water for 10 seconds, drain the hot water, then cover them all the way up with room temperature vinegar plus a little lime juice (and maybe some water if you like them less tart), a pinch of salt, a handful of sugar, and maybe a few spices. Let cool and then keep in the fridge for a week or two. They're pickles as soon as they cool down.

SLOW: Slice a red onion into thin wedges from tip to root. Cover them about 2/3rds of the way up with room temperature vinegar plus a little lime juice (and maybe some water if you like them less tart), a pinch of salt, a handful of sugar, and maybe a few spices. Throw them in the fridge and stir once or twice over the next few hours. They'll be pickles in about a day. Keep in the fridge for a week or two.