What is this 90's anime with a dragon and a sorcerer?
The show you are looking for is called Orphen , also known as Sorcerous Stabber Orphen

It was aired in 1999


Main character is a sorcerer -





Friend turning into a dragon - 



  Krylancelo Finrandi once attended the most prestigious school of sorcery on Kiesalhima continent, the Tower of Fang. He was sent there as a young child from an orphanage, along with another orphan girl called Azalie. Throughout the years, the two were very close, with Azalie becoming more and more powerful and Krylancelo looking up to her as a sister/mother figure and a best friend. It isn't until one day, Azalie's thirst for knowledge and extracurricular experimentation backfire, and she is horribly transfigured into a hideous creature, a dragon-like beast that departs the Tower in an animal fury, leaving Krylancelo behind





Milkshake scene:


About 7 minutes into the first episode, the main character spills his milkshake/icecream/parfait thing:



He then magics it back together again