Sacha & Sons at Mandarin Gallery sells New York-style Jewish deli food. Think bagels and lox, corned beef on rye, toast with schmaltz and chicken skin, and latkes.
A is very happy with the Reuben here - pastrami with sauerkraut. For me, I prefer Sacha's roast beef. It's rare, tender and very sweet and flavourful.
If you're here in a larger group, you can opt to share their platters too. There's a meat platter and a fish one. Except for a really good smoked trout dip though, I think the meats here are far better than the smoked fish.
Finally. One of only two places in Singapore to get a decent Reuben.