We are going to stay in Lisbon this summer for 2 weeks. Which Lisbon restaurants offer the most authentic taste of traditional Portuguese dishes like bacalhau à Brás or cozido à portuguesa?
In general, what you want is called a Tasca. These usually are very basic, small, bars and restaurants that serve a short list of classic dishes. Some places though use the term Tasca, but are full blown restaurants, even fine dining, so let the menu and cost guide you. There are literally dozens of places, maybe more, probably one local to where you are staying. Be warned though, some are cash only.
I thought this blog did a good job describing them and giving suggestions: https://oladaniela.com/tascas-lisbon/
We would recommend Velho Macedo (Rua de Magdalena 117, Lisboa). Small family-run restaurant: Husband runs the restaurant while wife is a fantastic chef. Best traditional meal we had in Lisboa. Enjoy!