You can find it at Conscious Eatery!
Maybe it's at Conscious Eatery?

Life, Buddhists remind us, is suffering. But other people's suffering is reliably worse than our own. Conscious Eatery, a restaurant and catering company located at 5620 6th Ave S, Building T (between the ID and Georgetown), is attempting to redress both of these situations in a small, delicious way, by offering free grilled cheese sandwiches to all comers (one per comer, to be precise) on Friday from 11 am to 1pm. They'll also have their full lunch menu available, which is tasty. No purchase necessary, but they will be accepting donations.

I'm not sure whether CE's main order of business is food or philanthropy, but their promise is that for every meal they sell, they donate one to people who need it, working with the local groups Mary's Place, Roots Young Adult Shelter, and St Vincent de Paul to get food to people attempting to survive the scourge of being homeless in Seattle. In the year they've been open, they claim to have donated 5,000 meals to hungry people.