We went to Num Pang Sandwich Shop for its opening weekend in March. Here's an excerpt from our review:

Although the sandwiches are tiny, they are delicious! We shared three: peppercorn catfish, veal meatballs and grilled skirt steak. They all had shredded carrots, cilantro and some sort of mayo-based sauce. Needless to say, they were incredibly flavorful and even though the seating was limited, we managed to squeeze into the upstairs bar.

So when I saw this recipe and remembered how much we loved the sandwiches, I had to try it.  I may never go back to the restaurant again : )

Although we didn't use butter, piquillo peppers or cilantro (none of which we had on hand), the sandwich still had tons of flavor!  We substituted low-fat mayo and added grilled chicken and arugula for a little extra veg + spice.