Counter-service restaurants with expansion plans have entered the market, too. Kolache Mama, a Houston chain that opened a New York City branch in 2009, proclaimed that the kolache (which it reinvented in flavors like the Reuben) would become “the new bagel.” But that Manhattan outpost closed after several months, and plans to open satellites in Boston, Chicago, Atlanta and other cities fizzled.

Kolache Factory, founded in Houston in 1982, has been more successful. With more than 30 locations in Texas, Kansas, Colorado, Missouri and Indiana, it sells chicken enchilada and Philly cheesesteak kolaches that show how far this pastry has strayed from its roots. This proliferation has been driven in part by Czech-Americans themselves. At festivals sponsored by Czech-led churches and civic clubs, which can attract thousands of people, polka bands play, church matrons cook Praha (a Czech version of goulash) and bakeries serve traditional poppy-seed kolaches. In Ennis, Tex., which holds a polka championship each summer, a grocery store helps finance community classes where Czech baking traditions are taught.

More influential, though, has been the rise of those roadside emporiums, selling everything from beer to deer stands to spiral-bound cookbooks, said Ms. Orsak, whose grandmother came to Texas from Moravia in the 1880s. Many Texans, no matter their heritage, now consider kolaches road food, best purchased at a Czech Belt rest stop. (In April, one of them, Czech Stop in the city of West, drew national attention when it stayed open to serve rescue workers after the deadly explosion of a nearby fertilizer plant.)

Now expatriate Texans in places like Portland, Ore., have begun to build customer bases at restaurants like Happy Sparrow Cafe, which serves Nutella-and-banana kolaches. Autumn Stanford, who owns the Brooklyn Kolache Company in that borough’s Bedford-Stuyvesant neighborhood, takes an artisanal tack, selling fruit-filled kolaches like apricot, as well as savory ones stuffed with bacon-wrapped hot dogs of Mexican-American derivation.

The inspiration for her business came from the roadside purveyors.

“My kolache story doesn’t involve Grandmother making them in the kitchen,” Ms. Stanford said. “Growing up in Austin, I didn’t even know they were a Czech food. When I was young, both sets of my grandparents lived in Houston. And when we went to visit, we always stopped at Weikel’s, in La Grange, for a bathroom break and a box of kolaches.”

One recent afternoon at Weikel’s Bakery, Pat Thomas, who was traveling from Austin to Schulenburg, Tex., confirmed that road-food imperatives still drive many kolache purchases.

“I came for the cream cheese kolaches,” she said. “And the clean bathrooms.”

Many Czech-Americans here, rather than feeling threatened by new varieties of kolaches that may obscure the pastry’s origins, are so confident of their cultural and culinary patrimony that they embrace them. In that spirit, some church festival organizers have expanded their kolache bake-offs to include the category “other.” And old-guard purveyors like Hruska’s Store and Bakery, in business in Ellinger since 1912, now sell nontraditional cream-cheese-and-chocolate kolaches.