Don’t expect a mixologist conjuring up voguish craft cocktails or the hottest chef de cuisine staging the latest in trendy gastro-pub fare. At Rosie’s Restaurant and Pub, a Portland mainstay that opened in 1987, what you’ll find is basic, reasonably priced pub grub in a friendly atmosphere reminiscent of Cheers (the pub’s website even says so: “devoted regulars” have dubbed Rosie’s “The Cheers of Portland”).

Locals and the occasional tourist hang out, ordering from the impressive beer list, playing darts to the beat of low-decibel ’80s rock, glancing at the muted flat-screen TVs tuned to sports and news, and eating the (it must be said) often pedestrian food.

Stick with the burger, though, and you’ll go home happy. Rosie’s classic burger ($8.95) is a towering specimen of well-charred beef on a crusty roll, and it is colossally good – juicy, beefy and flavorful. It arrives at the table in classic style, in a red plastic basket with a mound of French fries. (Rosie’s offers eight other burger choices, from Cajun to Mexican to a blue mango veggie burger). On my visit, the classic, an inch-thick patty, was cooked medium rare, just as ordered. The hefty bun – which comes in whole-wheat or white – couldn’t withstand the onslaught of the juicy meat and fell apart. But this is a minor complaint – messy eating suits a burger and it suits a bar. About those fries, they were standard issue, not awesome but not objectionable, either. If not hand-cut, at least they were crispy. For about $10, including a large, bottomless soda, Rosie’s burger is a far better value than any you’ll find at the crop of mid-level burger chains proliferating in the Old Port.

Rosie’s, which is housed in a 1902 building along the cobblestone streets of Boothby Square, is open for lunch and dinner. The all-day menu of hefty sandwiches and simple entrees are decently prepared and reasonably priced. Diners at a neighboring table ordered hearty sandwiches of fried haddock on a bulky roll ($9.95) and grilled chicken breast ($9.95) oozing with blue cheese and bacon. The sandwiches smelled good, and they disappeared fast. Mental note: try those next time.

Much of the menu is classic bar fare, such as two-meatball parm sliders ($8.95), fish and chips ($11.95) and clam cake dinner ($8.95). But you can also order from the blackboard specials, which change frequently. A crab and scallop chowder ($5.95), on special recently, was a good choice. The duo of shellfish added bulk to a creamy soup base that tasted of the sea.

Customers can also pick their location, choosing between eating at the bar or nearby high-top tables or in the adjacent dining room, a cozy room with comfortable chairs around shiny butcher block tables. With the Nickelodeon Theatre just a few blocks away, Rosie’s is a popular spot to drop in and grab a bite to eat before or after the movies. On a recent visit, an assorted crowd filled the dining room and bar: hipsters; plaid-shirted guys, some with tats and paunches, some with gal pals; and a few lawyerly types in suits from the nearby office towers – the same cross-section found in many a downtown neighborhood bar.

Happily, the music isn’t too loud at Rosie’s, nor was a group of khaki-wearing guys playing darts in the back of the dining room. Though it’s a bar, diners could actually carry on a conversation.

The cozy atmosphere is nice. The problem, too often, is the food. The meatloaf ($11.95), the chicken enchiladas ($10.95) and the fried calamari ($5.95), all blackboard specials recently, were all disappointing. Fried calamari is often reliable pub food. But Rosie’s version was tasteless and skimpy. The cup of acidic marinara it was served with didn’t do it any favors. The meatloaf was dry and came with very salty gravy. At least, it was partially redeemed by the tasty vegetable sides – creamy mashed potatoes and a mix of al-dente carrots and broccoli. The menu promised a chicken enchilada ($10.95) with a side of rice, salsa and sour cream. But the rice came inside the enchilada (and the chicken was sparse) while the salsa was omitted entirely.

Did I order badly? Were the specials a mistake? On prior visits, I’ve found the grilled sesame ginger salmon ($14.95) to be a good take on Asian flavors; the southern fried chicken soulful and with crunchy skin and tender meat ($10.95); and Rosie’s shrimp scampi ($14.95) respectfully zesty and garlicky with tender shrimp.

Our waiter told us that peanut-butter pie is the only dessert made in house. Unfortunately, it wasn’t available the evening I tried to order it. On a later visit, I sampled the pineapple upside down cake, made, our waitress said, by Sysco, the global restaurant supply house. The cake, served steaming hot from the microwave, boasted the requisite pineapple ring crown and sticky-sweet, syrupy glaze, and was topped with swirls of whipped cream. If you must have dessert, this hits the spot.

Rosie’s has an expansive beer menu with 15 draft beers from breweries around the country and an interesting selection of hard cider draft ($3.00). The scope of the list is impressive. The pub also offers nightly beer ($2.50) and bar food specials, like a dozen wings ($10.95) or calzones ($8.95).

Places like Rosie’s are fading fast from our food and drink scene in Portland, edged out by new trendy nightspots that offer $11 craft cocktails and $15 high-style small plates. If the food is a mixed bag at Rosie’s, so be it. Go for the darts, the drink, the burger and the pub’s convivial, welcoming, old-fashioned vibe.

John Golden, who lives in Portland, writes about food, dining and lifestyle subjects for local and national publications. He can be reached at:jdgmaine@gmail.com