Cafe Saigon, Maria de Molina 4 (corner with Castellana) - Reservations 91 563 1566
Probably the better know out of this pack (and now has some other restaurants from the Group in Madrid and other cities (San Sebastian's Maria Cristina Hotel has one) . Usually very busy in the weekends (impossible to get a table without a reservation, having 2 serving shifts), but you will get easily get a table during the week although it is always lively. The decoration is superb (which is even more surprising as there are on the bottom of a office building), high ceilings, very good service and good food. They have good combo menus but the "a la carta menu" is also good. Has one of the best noodle soups in town, called "Sopa de arroz Vietnamita" (which could also be a main), very good green salad with duck, great noodles (3-4 types nromally) and good fish and seafood plates, among other things
A recent discovery and not very well know is Asia Xang
+34 914 134 920 Paseo de los Cerezos 2. Very closed to the corner of Ramon y Cajal with Alfonso XII, on a very quite area, very easy to park on the street (a plus on a busy weekend in Madrid) and with an amazing terrace in the summer (just by the street, quiet and relaxing and always great temperature at night) but the inside of the place is also nice and well decorated. I have never had a problem finding space but could be quite busy on the weekeds. It has a number of combo menus, ranging between combining chinese and thai to a more japanose one. Decent sushi, great dim sum (probably the best I have had in Madrid), great squid and St Jacques grilled with a light soi sauce, good teppanyaki de solomillo y el "maki california". Service is always friendly and you can eat for 30 Eur a piece, even cheaper if you try,
Definetly you should give it a try
Others worth a try could be
China Crown, Calle de la Infanta Mercedes 62 28020 Madrid - 91 572 14 64
A bit more expensive than the others, around 40 Eur, but good food, and always a nice atmosphere and a bit different plates than the usual ones
Don Lay, Paseo de Extremadura 30+34 914 634 546
A wear looking restaurant (as it was an old meson castellano in which they have basically change nothing but the name), it does serve a great sunday Dim Sum. My cousin whom is Taiwanese always takes us there. That is a good recommendation for sure