Penn's is a little-known Henderson gem. A hole-in-the-wall place known only by Henderson locals. Located in a dingy area off of Sunset and the 95, you would completely miss this place if you don't know what you are looking for.
The place is small. I mean seats no more than 20 people small. But that's ok - because the food is delicious!
I personally recommend the Kra Prow. Now, this is a spicy dish, so I usually recommend a 2 or 3 on the spice level (unless you particularly enjoy face-numbing burn). They use fresh basil, which gives it a cooling effect.
In addition, the Panang Curry with Chicken is wonderful. The flavor is a creamy over-the top coconutty spice that delights the tastebuds (really, it does).
The only downside - the area, and the decor.