Dorothy Mengering, a Midwestern homemaker who became an unlikely celebrity in her 70s as she baked mystery pies and covered the Olympics on the late-night show of her son, David Letterman, died April 11 at her home in Carmel, Ind. She was 95.

Letterman publicist Tom Keaney confirmed the death but did not provide a cause.

Letterman had been on the air for years and had made ironic celebrities out of dozens of nobodies before he thought to bring on his mom. But the moment he did, she became a hit, with a cheerful “Hi, David!” in her Indiana accent starting every appearance.

The two had great on-air chemistry, her homespun sincerity proving the perfect foil for her son’s urban acerbity.

Her first appearances came via satellite from her Carmel kitchen for a segment called “Guess Mom’s Pies,” which became a Thanksgiving tradition. Letterman would make a huge production of the bit before finally declaring, usually correctly, “Chocolate chiffon!” or “Rhubarb!” When he was wrong, she would take on a comforting tone as if he were a boy who had lost a Little League game.

Dorothy Mengering in 2004. (Kurt Hostetler/Associated Press)

She soon started making annual Mother’s Day appearances, too.

Mrs. Mengering was a correspondent for Letterman’s “Late Show” on CBS at the 1994 Winter Olympics in Lillehammer, Norway, a role she reprised for the next two Winter Games, wearing bulky snow gear that made her tiny self almost invisible and oozing pure sincerity even in the absurd bits Letterman’s writers had her perform.

“After Lillehammer, I couldn’t believe how it all took off,” Mrs. Mengering told the New York Times in 1996. “I think it’s about the idea of mom and of a family.”

Dorothy Marie Hofert was born in Linton, Ind., on July 18, 1921. She married Letterman’s father, a florist named Harry Letterman, in 1942. He died in 1973, and she later married structural engineer Hans Mengering, who died in 2013.

Once famous, she put out a cookbook, 1996’s “Home Cookin’ With Dave’s Mom,” that included recipes such as “Dave’s Fried Baloney Sandwich” and the secrets behind many of the pies she had baked for the show.