I recently tried the famous $3.50 dessert on Amtrak. I instantly understood why it has a cult following.

Amtrak's buttercake wowed me more than some fine-dining desserts and quickly became my favorite train perk. Kristine Villarroel/Business Insider

I've spent thousands of dollars and hundreds of hours traveling on Amtrak , and, like anyone who travels regularly enough by train, I can tell you that the food isn't always particularly showstopping.

But one menu item during a recent long-distance trip wowed me more than some fine-dining desserts.

In fact, it made my nearly $1,000 first-class ticket worth it — and I'm far from the only one obsessed with the unique regional dessert.

I've traveled long-distance on Amtrak many times, and the food isn't always my highlight

I've traveled nearly 10,000 miles aboard Amtrak trains, mostly in coach.…