Ah! ok, I think I remember now, the cut through soi leads to soi 15, coming up near that big school compound.

If you're ever looking for a high quality (but more expensive than Krua Khun Puk etc of course) option on Soi 11, maybe for a date etc I'd recommend Burapa.  It specialises in Eastern Thai food, lots of good seafood and some unusual dishes that you don't see often. It's tje sister restaurant to Sri Trat which is one of my favourite places further up Sukhumvit on Soi 33. The restaurant has a good atmosphere,  it's decorated like the Orient Express train and is also a good spot for a few drinks. Not somewhere that I'd recommend for a cheap meal when out mongering but a cool place if you want to take someone out to a very nice restaurant that would still be cheaper than most other date type venues we've discussed previously here and with food that would probably be better than most of them too IMO, for Thais at least.

I’d ask you guys to give Bangkok Burgers go. It is at the top of soi 11, just a you come in from Sukhumvit, next to the 7/11 (141 Soi Sukhumvit 11, Khlong Toei Nuea, Watthana). The burgers are cheap and pretty good. 
most of all, they serve good Thai food on the top floor. I really enjoyed their Tom yom goong, particularly prawns, tamarind prawns and other dishes. The Tom yum came with a good number of fairly large prawns, fresh too and the soup was just glorius. I must have eaten there 3 or 4 times. Although on the top floor, there is an open air area where tenants (also a dorm/hotel of some kind) where guests smoke cannabis. The smell is excruciating. Especially when you’re trying to enjoy your food. 

I love this place, always pop in here at least once on each visit to BKK.

@ethanhunt -  Hey sorry about this. I just spotted it. I have attached a screen shot from Google maps. And the address is 32, 2 Soi Sukhumvit 13, Khlong Toei Nuea, Watthana, Bangkok 10110. There is a laundry shop at the corner but I cannot recall a beauty parlour.