IT IS A rare bird who can make Taco Tuesday at Portland, Oregon’s most celebrated Italian restaurant simultaneously more confounding and comprehensible. And in fact, interior designer Andee Hess is an exotic species in a city that continuously squawks about its superior strangeness and, conversely, in an industry that is flying towards globalized homogeny.

“Do you eat alone at bars often?” Hess leaned across the marble counter at Ava Gene’s — which, incidentally, she designed — to ask me. The question was perplexing, as I’d just moved to Portland from New York City, where solitary dining is a communal pleasure. Yet, our surroundings somehow helped make sense of the baffling inquiry and incongruous menu.

While resolutely site specific, Hess’ interiors reliably entwine their owner’s personal nostalgia with clever material play and original details. The results are equal parts eclectic and elevated, allowing both commercial and residential projects to create space for unscripted expression and enjoyment, such as hyper-seasonal tacos paired (delightfully, it turns out) with prosciutto and Prosecco.

Since that auspicious evening nearly five years ago, I’ve learned that our encounter was very on-brand for Hess: Brazen curiosity is a critical ingredient in her kaleidoscope philosophy.

As the principal and founder of Osmose Design, Hess is also the magpie eye behind the novel interiors of several of the city’s other internationally renowned culinary destinations — The Woodsman Tavern, Smith Teamaker, and Salt & Straw among them — and the award-winning homes of many of its best-known residents, be them art patrons or certain former “Saturday Night Live” cast members. Further, she works as a consulting creative director for domestic and international hospitality brands and is in the throes of developing a performance space for the Portland Art Museum. Then there are the custom furniture and lighting projects perpetually in Hess’ back pocket, such as a carved bespoke Korean bathtub currently in the works for one of her numerous residential clients.

It’s an impressive but seemingly motley mix, unless you understand what makes the designer tick. “I am doing this work because I love to connect with people,” she confides. “I love the psychology of design, exploring the how and why people make decisions.” For a recent project, this probing exercise involved stirring up an owner’s Parisian nightclub past to transform an opaque “French design” ask into provocative disco moments inside his genteel Tudor-style family home. For another, it involved a study in surrealism that reflected its inhabitant’s phantastic tendencies, complete with undulating ceilings and refrigerator handles packed with tiny faux candy. In the case of a notable Los Angeles–based client, it meant layering a cinematic lineage with the proprietor’s spooky predilections to create a design with “strong Vincent Price meets Devo vibes,” an inscrutable description that reveals Hess’ own unconventional inclinations.

“Everyone’s lives are unique, and everyone’s stories are unique,” she explains. “Why would you want to walk into a home that looks like me, when it should look like you? Especially now, everyone’s starting to see the same things, so you could really get caught up in a trend and not have a conceptual, or even philosophical, basis for your decisions. I try to push my clients to challenge themselves, to explore some depth.”

This insistence on scratching below the surface and using what she discovers to manifest the idiosyncratic is perhaps Hess’ most definable aesthetic signature. It’s why her work historically precipitates rather than reflects trends, and why she’s considered a designer’s designer. It also guarantees that if you’re dining alone at a bar she’s created, she’ll invariably ask why.