There is a new French restaurant in Calle Iglesia called Le Telegraphe, it is where Maison Eve used to be or try Gregorio del Pescador next door.
Unfrotunately my favourite place Bodeguita El Andaluz is closed for Xmas Eve and Xmas Day but I am booked for New Years Eve.
Los Pepes is doing 3 courses for 45 euros (see thread in Restaurant reviews for phone numbers etc)