In addition to everything in the Porta Underground Mall, there are a lot of restaurants on the 10th and 11th floor in the station - Kyoto Station Dining. Take the escalators all the way up to the 11th floor and then through the door on the right. The ramen restaurants are on the 10th floor - take the escalators up to 11 (you can't get off at 10), cross over to the other side (left) and back down the steps to 10 and then through the door on the right. All the ramen restaurants are good though our favourite is Iroha - try the Tan Tan Noodles. On the 11th floor (see the 'Eat Paradise' group in the link above), we've eaten quite a few times at Mimiu and also at Waco (which is more or less opposite).