Porter, D-California, had asked if Carson could explain disparities in REO rates.
REO refers to "real estate-owned properties," which are typically homes owned by banks in foreclosure.
Carson didn't seem to hear her and responded: "An Oreo?"
"No, not an Oreo," Porter said. "An R-E-O."
"Real estate?" he asked.
When Porter asked what the 'O' stood for, Carson responded "organization."
So Porter went on to explain the term.
Porter later tweeted a video of the exchange.
"He thought I was referring to a chocolate sandwich cookie. No, really," she tweeted.
When asked by ABC News if Carson had indeed confused the foreclosed homes with a cookie, spokesman Raffi Williams responded: "Given the amount of acronyms used in Washington, when the secretary has conversations about foreclosed properties he calls them what they are: foreclosed properties."
Carson seemed to take the misstep in stride, tweeting a photo of himself with a handwritten note to Porter and a package of Oreos he promised to send her way.
Carson's hearing included other memorable moments. After a female congresswoman challenged Carson on his budget and housing policies on Tuesday, Carson responded by urging lawmakers to “think logically rather than just emotionally."
Rep. Nydia Velazquez, a New York Democrat, called Carson’s proposed budget “shameful” and “immoral” because she said it didn’t include enough money to address the nation’s housing crisis, citing the more than 4 million people waiting for housing assistance.
Carson was prevented from immediately responding because the congresswoman's time was up. But Republican Rep. Bill Posey of Florida said he’d use his time to let Carson respond. That's when Carson said, "We have to use our brains."
“We have to think logically rather than just emotionally if we’re going to solve these problems," he told the committee. "And they can be solved if we work together, rather than making everything into a political platform and trying to score points.”