How to chase a dream espresso shot?

I make a decent shot of espresso. Mostly using Italian Roast beans from a good local roaster in Portland, Maine. I dare say my shots are as good as most of the coffee shops I visit (at least most of the time) and occasionally (on a good day) better. But some years ago I had a shot of espresso at the 9th Street Espresso stall in the Chelsea Market in NYC. It was the best shot I’ve ever had. It was quite a short shot, but amazingly sweet. In fact it was the shot that introduced me to the idea that espresso could be sweet!

Now, I know that memory can be a great amplifier, but my shots have not come near what I remember of that one. How would you approach the project of achieving a shot like that?