No one is happier than I am that I’ve carved out some weird and awesome niche as a Mets and sandwich writer. And I am so very grateful that a non-zero number of human people want to read what I have to say about the Mets and sandwiches that I’m driven to do the best damn job I can covering this beat, especially when that entails eating sandwiches at Mets games. So I hoped to eat the first Original Filet Mignon Steak Sandwich served at Citi Field.

I failed. When I got to the new Pat LaFrieda stand in Citi’s center-field concession area on the Field Level concourse shortly after 5 p.m. on Tuesday, there were somehow already a few people ahead of me on line. I suspect most if not all of them were Mets employees, so I can vaguely lay claim to eating the first Original Filet Mignon Steak Sandwich served to a civilian at Citi Field. But typically everyone who doesn’t work at SNY blurs the line between the network and the Mets so it’s not even worth making the case. Whatever. I ate one of the first Original Filet Mignon Steak Sandwiches served at Citi Field. It looked like this:

Maybe it’s not much to look at, but on that sandwich are three nearly burger-sized pieces of steak from famed meat purveyor Pat LaFrieda, who is the only person I’m aware of that can accurately be described as a “famed meat purveyor.” The guy provides meat to many of the best burger places in New York and the stand at Citi Field represents his first foray into retail.

The sandwich is prepared on a hot, flat grill. The woman behind it laid down the three pieces of steak and some caramelized onions, then spread slices of Monterey Jack cheese on top of the onions to melt. When the steak was ready, the man next to her distributed the pieces evenly on a split french-bread hero, shoveled on a layer of melted cheese and onions, then added a scoop of something the press release described as “secret au jus.”

The Original Filet Mignon Steak Sandwich costs $15, steep for a sandwich even inside a ballpark. But the thing is delicious.

Fun fact: Before I started writing about sandwiches, I was way pickier about the ingredients that go on my sandwich. If I were ordering this with no plans to review it, I’d have asked for no onions, as onions — especially slithery sauteed onions — typically turn me off.

But I have found in this pursuit that a great sandwich can make me understand and appreciate an ingredient I previously did not. That’s what happened here: the onions and the oniony au jus add a lot of flavor, a wealth of sweetness that complements the steak and cheese and is absolutely essential to the sandwich as a whole.

The steak is so good. When I watched the woman prepare the sandwich I worried the unsliced pieces of filet mignon — way larger than you normally see on steak sandwiches — would prove difficult to chew through in a single bite of sandwich. Fret not: It’s prepared rare, and it’s so tender it bites almost like a burger. I tried my best not to be biased by the brand and to assess the meat on its own merits, but within two bites I was thinking, “damn, this Pat LaFrieda dude is the f—ing balls.” To boot, it’s got a pleasant black peppery seasoning that gives the sandwich a touch of spice.

The cheese feels like more of a binding element to affix the onions to the steak than anything else, but the creaminess it added was certainly welcome. And the bread was fresh and sturdy, toasty and crunchy on the outside but soft with au jus on the inside.

It’s a hell of a sandwich, on the same tier with the Shake Shack burger and Blue Smoke pulled pork in what has to be the greatest sandwich ballpark in all the land. My only quibbles with it are that there might have been a touch too much of the onion flavor (even necessary as it was), that it’s a bit messy for ballpark fare, and that it’s $15.

Here’s why I suck at this: While I was wolfing it down over one of the standing picnic tables out in center field, a guy in a chef’s jacket approached me and introduced himself as an Executive Chef at Citi Field. He noticed that I was eating the sandwich and wanted to know if I had any feedback.

Seems like a great networking opportunity just fell in my lap, no? I knew I should tell this guy that I actually write about Citi Field food all the time and try to strike up a conversation, and maybe he could become a valuable source or at least hook me up with free food. But I’m awful and awkward at networking and self-promotion, plus I was too focused on enjoying the sandwich to think about much else, so I panicked and said, “uhhhhhhh, the meat is really good!”

It is, though.