The burger: Nothing goes to waste in a restaurant kitchen. Particularly when the material in question is prized scraps of beef — in this case, bavette (France's sort-of tenderloin cut) from premium purveyor D'Artagnan. The pieces are trimmings from the grilled bistro steak (a steal, by the way, at $25) at Blackbird Cafe, and they're the backbone for a fantastic burger.

Chef/co-owner Chris Stevens incorporates them — along with fattier brisket — into a coarse grind, adds a bit of salt and pepper and forms the ground beef into roughly-shaped 4-oz. patties. They're grilled straight through to a flat-out medium on the flattop, giving the patty's exterior a wonderful caramelized char but not draining the deeply flavorful meat of its essential juices.

Stevens deftly handles them a few ways. During happy hour (2 to 5 p.m. Monday through Saturday, and 9 p.m. to whenever the kitchen closes Monday through Thursday), they're the centerpiece what's billed as a "no-frills" (and no-substitutions) burger: a slice of American cheese, raw or slow-cooked onions and a few well-made house-made pickles, with ketchup and mustard on the side. It's a model of burger restraint, and burger fabulousness.

Last spring, Stevens began devoting Tuesday evenings to burgers, getting playful with a handful of more elaborate variations. It's that same patty, of course, but then out come the toppings. And how.

For the past few months, Stevens' play on the classic California burger (dubbed the "Brian Wilson" of Beach Boys fame, "because 'California burger' is such a boring name," said Stevens with a laugh) has been a fixture, with its tangy red onion (it gets both pickled and grilled), crunchy romaine lettuce, creamy avocado and "special" sauce (it's pictured, top).

On Tuesday night, I dug into (and totally dug) the light-and-bright "Pineapple Express" (pictured, above), so named because of a slice of juicy, tart-sweet pineapple that's slipped under the patty. There's also long, thin, crunchy cucumber slices, cool grilled tomatillo salsa, refreshing cilantro and swipe of smoked paprika aioli. As flavor combinations go, it's a total classic-in-the-making.

Attention must be paid to the house-baked bun. It's easily one of the Twin Cities' best, a brioche-style beauty that's loaded with butter and egg yolks, a super-rich formula (translated from a dinner roll recipe) that makes for a peak burger-bun experience. Each one gets a brush of butter (because, truly, butter makes everything better) and a light toast on the grill, warming the bun and nudging even more flavor into its rich, tender texture. If Stevens sold them in packages of six, he'd make a fortune.

Price: $6 at happy hour, $10 on Tuesday evenings. Both are massive bargains. Stevens is no fan of substitutions, so caveat emptor. On Tuesday evenings, all add-ons are $1 a pop, and that includes such basics as lettuce, BBQ sauce or onion; bacon, gaucamole or fried eggs each cost an additional $2.

Drink up: On burger night, Stevens and his spouse/co-owner Gail Mollner will toss in a pitcher of Surly's fabled Hell (a golden, floral lager) for $12. That's a very good price.

Fries: Extra, and worth twice (or more, to be honest) the $2 price. They're simplicity itself, just super-starchy russet Burbanks, peeled and hand-cut. They're blanched in a lower-temperature (275 degree) fryer, then cooled and refried — to golden, tantalizingly tender crispiness — at 375 degrees. They've got a deep, potato-ey flavor, and the insides radiate a kind of baked potato goodness that's clumsily eviscerated by most deep-fryers.

Here's hoping: Every time I drop in on this ultra-charming, runs-like-a-Swiss-watch restaurant, I wonder if the Kingfield neighborhood knows and appreciates what a breakfast-lunch-dinner gem it has in its midst. Here hoping that the answer is a bold, unequivocal yes.

Address book: 3800 Nicollet Av. S., Mpls., 612-823-4790. Open 8 a.m. to midnight Monday through Saturday, 8 a.m. to 2 p.m. Sunday.

Talk to me: Do you have a favorite burger? Share the details at rick.nelson@startribune.com.