Sounds like Ethiopian food would be a perfect fit if you avoid the chicken dishes (they are often served with a whole, hard-boiled egg added in) and confirm the restaurant only uses teff (a type of millet) in their injera. I would suggest Das in Georgetown or Dukem on U Street, as many of the other popular restaurants are small mom-and-pops that might be more difficult to coordinate the special dietary needs. Note that some dishes are traditionally cooked with butter so you’ll need them to walk you through those. But it is clarified butter/ghee, in case the milk solids are the allergen.