A Twin Canterlots story—last in Cook’s Tour; followed by Virga

“Cook, that’s the fanciest—and stuffiest—restaurant around here!” Sunset looked and sounded aghast. “What’ll I wear?”
  I let my eyebrows rise. “This from one of the girls who magic up spiffy new ensembles every few weeks?”
  By rights her glare should have reduced me to cinders. “That’s different and you know it. This isn’t even like a Rainbooms gig, where I can get away with something outrageous. Whatever it is must be pretty serious or you wouldn’t be so insistent—and evasive; don’t think I haven’t noticed.”
  When I simply shrugged, she sighed in resignation. “Fine. I’ll talk to Rarity and see what we can come up with on my pitiful budget.”

Takes place during winter break of senior year—middle of season 6.