Las Vegas developer Scott Goldstein is pushing ahead with plans for a new office building in Southern Nevada — and with a new neighbor poised to serve up decadent milkshakes. Goldstein, founder and managing partner of real estate firm Prospect Street Capital, held a ceremonial groundbreaking Tuesday for Deer Springs Commercial Center in the northwest Las Vegas Valley. Plans call for a two-story, roughly 34,000-square-foot office building with for-sale units, and a neighboring standalone milkshake spot — called Shook Shakery — from Nothing Bundt Cakes co-founder Dena Tripp. The project site is on Deer Springs Way just east of Durango Drive, across the street from the Centennial Hills Hospital Medical Center campus. Site work is underway, and Goldstein said he aims to finish the office building by year’s end. Tripp said she expects to open Shook Shakery in the latter part of the summer. She described its offering as a “cake shake,” as baked cake will be incorporated into the milkshake.…