The Lentos Art Museum sits on the banks of the Danube. (Hemis/Alamy)

When I heard that a new opera house was opening in the Austrian city of Linz, the news should have spurred lyrical memories of Mozart’s Linz Symphony or the thundering notes of Anton Bruckner, who grew up nearby. Instead, I suddenly tasted the finely ground hazelnuts mixed with lemon-infused spices that made up my favorite childhood pastry: the Linzer torte.

Details: Linz

Growing up in Geneva, I spent most Tuesday afternoons enduring a painful piano lesson. But after each one, my Parisian mother, well aware of my growing obsession with sweets, would take me across the street to the corner pastry shop, where she let me pick out a treat from among as many as 20 cakes. Every time, I chose the Linzer torte, a pastry filled with raspberry or currant jam and topped with a lattice crust. I can still taste the crumbly, buttery dough and the pungent jam, and recall the way my one-on-one with composer Carl Czerny would recede from my consciousness and melt into pure pleasure.

Now settled in New York, I’d leveraged my sensitive palate into a busy career as a food and travel writer. I decided to travel to Austria and, channeling Gretel, follow a path of torte crumbs around Linz and into its new opera house.

Since 2009, when it was named a European Capital of Culture, the small city that straddles the Danube between Vienna and Salzburg has made tremendous strides in shedding its stark industrial reputation in favor of a quasi-futuristic modern image.

“First we cleaned the air,” said Horst Hörtner, senior director of Futurelab, an innovation think tank at Ars Electronica, a digital media and technology museum housed in a striking multicolored, LED-lit glass cube on the river. “Then we cleaned the water, created a car-free zone and gave the town a facelift.”

And last year, his crew also invented a microchip that translates sound into light. “As a wink to our culinary heritage, we painted it red and called it Linzer Schnitte [meaning slice],” he added. I was onto something.

Sweet origins

I cross the Nibelungen Bridge, headed back to the past and the city’s old town.

“It suddenly dawned on me that the Linzer torte connects much of our history,” said Ute Sailer, a city guide who recently came up with a “Linzer Torte Tour.” We’re standing on the Hauptplatz, the main square, lined with pastel baroque facades. “There’s been a weekly market here for the last 800 years,” Ute adds casually.

She leads me on the short walk to k.u.k. Hofbäckerei, the oldest bakery in town. It’s helmed by fifth-generation baker Fritz Rath, a favorite of expat Dennis Russell Davies, music director and chief conductor of the Linz Opera and the Bruckner Orchestra Linz.

“No! We don’t put no raspberry jam in the torte,” roars Rath, a genial goblin who seems to have sprung straight out of a box, in charmingly ungrammatical English. He bounces back to his kitchen, gesturing for me to follow and don an apron. I dig my hands into the dough as he guides me through the making of my very own torte. I can’t resist licking a spoonful of red currant jam. “Here in Upper Austria,” explains the baker, “red currants grow everywhere, like weeds.”

While the torte bakes, I chat with Liselotte Schlager, author of a cultural history of the pastry, in the nostalgic cafe plastered with memorabilia from the heyday of the Austro-Hungarian Empire. “It’s one of the oldest pastry recipes ever recorded,” she affirms. But from what year? Historians and bakers bicker over 1653 vs. 1696. But they all seem to agree that the ancient manuscript was discovered in the stunning baroque library of the Admont Abbey, about 50 miles away in the Austrian Alps, which houses more than 200,000 volumes dating from as early as the 8th century.

My Linzer torte is ready. I nibble slowly, layer by layer: the slivered, fragile almonds on top; the golden lattice; the sweet and sour notes of the jam; and then the moist hazelnut dough redolent of cinnamon and clove. “Don’t forget that in the 1600s, only the elite could afford spices or almonds,” remarks Ute, my diligent guide.

Later, she leads me to the Linz-Genesis Museum where, among Roman artifacts and tools from the Middle Ages, sit Linzer torte boxes from the early 1900s. They’re way past their sell-by dates, but their covers feature images of the “Schöne Linzerin,” the plump feminine ideal of the time. Later that night, I’ll learn that in today’s local slang, a hot chick is referred to as, what else — a Linzer Schnitte!

A night at the opera

On my way to the “new” cathedral, a dark neo-Gothic ship dating from the mid-19th century (the “old” one, where Bruckner served as organist between 1855 and 1868, was completed in the 17th century), I spot Gragger, a grungy shop featuring breads, cakes and an “all organic” sign. The dark breads are fabulous, but alas, their torte is dry.

In the evening, I shun the tramway and walk the whole length of Landstrasse, the main artery that leads to the sturdy steel-and-stone Opera House. The new building, imagined by British architect Terry Pawson, cost $236 million and has breathed new currents of life into the whole neighborhood.

It’s operetta night, and the full house settles in, under a circle of lights reminiscent of Carnegie Hall. No offense to Offenbach and “La Vie Parisienne,” but I soon slip out of my seat and climb the two flights of stairs to Das Anton, the gleaming open-kitchen brasserie, where celebrity chef Toni Mörwald offers Austrian cuisine with a modern bent.

“So is the restaurant named for you?” I ask innocently as the chef and I sit beneath a severe portrait of Bruckner. “Of course!” he trumpets. “Well, for me, and Bruckner.”

Mörwald has reimagined the Linzer torte as a vanilla parfait sprinkled with almonds, holding court beside a sphere of nutty dough that we’re expected to dip, lollipop-style, into a red currant compote. Delicious and clever.

The next day, the whole town is out to cheer the runners in the annual citywide marathon. On the Danube, now a clean blue, a fast boat pulls a water-skier. The waves are reflected in the glass facade of the Lentos Art Museum, where several Warhols, Klimts and Schieles hang. Some say that the nearby Brucknerhaus, a circular 1974 concert hall, was built in the shape of a Linzer torte. Perhaps it was.

On a quiet cobblestone square, a group of American women are enjoying drinks. They’re in Austria teaching English, and they laugh hysterically upon hearing what has brought me here.

“Linzer torte, it’s like a coffee cake,” says Celeste Maus. “Kinda dry.” But they insist that I check out Cafe Jindrak, where the official torte can supposedly be found.

Past and present

There are six outposts of the cafe in town, so I choose the closest one, just off the elegant Rudigierstrasse and its antiques and design galleries. But in the window of a concept store named Daschkaria, a postcard calls my name. Photographed by the co-owner, Daniela Köppl, it shows crumbs of Linzer torte and a fork on a paper plate. The card says simply: Once upon a time, there was a Linzer torte. “I thought it illustrated our town very well,” Köppl says.

But I’m after more than crumbs, so I proceed to Jindrak’s bakery. Talk about “official”! Leo Jindrak III is the only baker allowed to feature the Linz coat of arms on his boxes, an honor bestowed by the mayor in the 1970s. Jindrak is also famous for holding the record for the largest Linzer torte ever baked, with a diameter of 13 feet. How will this cake compare with my own, fresh out of the oven? I take a bite, a bit dubious, but the pastry is fabulous, with a clear hazelnut kick.

“But hazelnuts only appeared in the recipe at the end of the 19th century,” says librarian Waltraud Feissner, who, like the Empress Elizabeth before her, has collected dozens of recipes. “You know, every baker claims to have the original recipe, but I know they don’t. I counted as many as 80 original recipes!”

Next I visit Peter Hirsch, culinary writer for the local newspaper Oberösterreichische Nachrichten. “Have you been to Verdi’s?” he asks. “Erich Lukas, the fabulous chef, makes a torte in a glass.”

The next night, I hire a cab to drive me five miles outside town to Lukas’s charming chalet. Both Einkehr, the casual cafe there, and the gastro enclave, Verdi, are teeming with seemingly happy diners.

The torte in a glass turns out to be the Viennese Sachertorte, but from the bucolic terrace, I take my measure of Linz, spreading in the distance.

Suddenly I understand what’s happening here. For centuries, the history of the town and the history of its native torte have followed a parallel path. But now, Linz offers both scrumptious bites of its baroque past and glimpses of its ultra-modern present, in the shape of a lollipop or inside a glass building.

It’s a great combo.

Bigar is a food and travel writer in New York.