Some things never change. Luckily, the hamburger at Tessaro’s is one of them. The recipe has remained virtually the same since Kelly Harrington took over the restaurant in 1984 with the help of his sister and mother. When you enter, it’s guaranteed that at least one Harrington will greet you.

Dark wood paneling surrounds the bar area at Tessaro’s, and the dining rooms have exposed brick walls, many covered in murals. Large black fans spin leisurely from the tin ceiling amid the dim lighting. Though the lighting is dark, the warmth of the crowd creates an inviting atmosphere. There’s often a wait; on Friday or Saturday nights especially, it is not atypical to see people three-deep at the bar.

Despite the crowded vibe, the service is personal and unhurried. The bartenders and wait staff wear white button-down shirts, black aprons, and neckties, adding a touch of old-fashioned class to a restaurant that already embodies gentility. This feeling is reinforced by the way they pull out tables for guests taking a seat in the bar area.

Perhaps nothing exemplifies Tessaro’s appeal better than its clientele. On any given night, you are likely to see a cross section of Pittsburgh — distinguished-looking senior citizens, thritysomethings starting a night on the town, a single father with his children, nurses who just got off shift, and regulars from the neighborhood.

Most of them come to Tesarro’s for the burgers. Tessaro’s serves each half-pound burger on a hefty Kaiser bun, best ordered a juicy medium rare. The restaurant cooks its burgers on a large hardwood grill, bringing out the beef’s richness and tenderness. Unlike other establishments, at Tessaro’s a medium rare is a medium rare, warm red center and all. Your meat will come as ordered, not overcooked.

Options range from the classic hamburger to a bacon blue cheese burger. The gourmet cheeseburger, with sautéed mushrooms, caramelized onions, and crisp bacon, is particularly delicious. The taste of the mushrooms is overwhelmed by the beef, but the lasting sweetness of the onions and the saltiness of the bacon complement the burger perfectly. The flavorful meat can overpower some of the cheeses, especially the cheddar, which is lacking in sharpness. American cheese is always a safe bet, while blue cheese offers a more adventurous alternative.

Lacking from the side options are French fries, with home-fried potatoes serving as a somewhat unsatisfactory substitute. Instead, opt for the potato salad, sweet and creamy with a slight tang. Thick red potato skins and small pieces of celery round out the salad, giving it a nice crunch.

Tessaro’s also has a full bar. The beer selection is Pittsburgh-heavy, offering the likes of Penn Pilsner and Iron City. A pint of Sam Adams at $3.50 makes the wait to be seated more enjoyable.

As you leave, Harrington thanks you for your business, not because he needs to — Tessaro’s is a Bloomfield institution — but because that’s the type of establishment he runs.