What are the ingredients that make vegan meat taste like real meat?
The meaty taste is Umami. It is the flavour of monosodium glutamate, in the same way that salty is the flavour of salt.

Both mushrooms and tomatoes of the right variety are quite rich in it, as is yeast extract. You can also just buy the stuff commercially.

Don't worry about the stigma attached to it, it's not actually toxic or anything.