Where are the best places to eat in Madrid?

Hello Cheryl.  There are a lot of excellent options such as Mercado de la Reina, Taberna Alhambra, Lateral, Restaurante Palacio de Cibeles, La Gabinoteca, restaurante hegar, El Botánico and Viridiana among many others.  In general "the Spanish cuisine" is excellent; therefore I am completely sure that you will find outstanding options by walking the city.

Hope this helps! Saludos.