flavor (something) with (something)
To add something, such as a spice or an herb, to a dish to enhance or improve its flavor. I'm begging you, please don't flavor the guacamole with cilantro—I hate the taste of it. My Italian relatives love to flavor everything with garlic.
flavor food with something
to season a food with something. He flavors his gravy with a little sage. Can you flavor the soup with a little less pepper next time?