The baking legend admits some of the offerings were awful and even made her ill.
She has also hit out at fellow judge Paul Hollywood for being too honest – because she feels he was too harsh on the bakers.
Mary, 83, who left the series in 2017 when it switched channels from BBC One to Channel 4, said: “We did have a wonderful man and he made a beetroot cake.
It really was awful but we didn’t say it was nasty because he would get so upset.
He was proud of it. “There were quite a few things I didn’t like so much.”
It is thought Mary was referring to the black forest gateau containing beetroot, served up in 2015 by contestant Stuart Henshall, 38, a vegan nicknamed Hipster Stu.
She said: “People know when they’ve done something awful. it’s been so bad it made me feel quite ill.”
But Mary said Paul, 52, was not nearly so considerate in his approach
“We had great fun. He was brilliant at bread and I had my thing,” she said. “I could sometimes tick him off.
He was a bit harsh and I was trying to encourage people.
If they’ve done something wrong they know. “They don’t need to be told off about it, they need to know to how to have success next time.”
Hollywood stayed with the series when it switched channels and now judges alongside top chef Prue Leith, 78.
And she defended his approach.
“When you get the Hollywood stare, you never know what he’s going to say, whether ‘it’s terrible’ or whether he’s going to put his hand out and give them a handshake,” Prue said. “One of the contestants was really crying, because everything had gone wrong and it was terrible.
“And Paul said the flavour was fantastic, it was a really imaginative thing, well done.
Then he said, ‘But it was *****’.” Mary has since fronted a number of shows for the BBC including Britain’s Best Home Cook.
As Bake Off gears up for the start of another series, hosts Noel Fielding, 45, and Sandi Toksvig, 60, have told of their despondency when they took over from Mel Giedroyc, 50, and Sue Perkins, 48.
“It was like we’d been handed the crown jewels and were about to throw them in the river,” Sandi said. “There were 40 executives watching us try to be funny.
There was a lot of, ‘That’s not the Bake Off way’.” Noel added: “We were under an enormous amount of pressure to not ruin this sacred show.”
The duo are now firmly installed and their fresh approach has won praise from viewers.
And Hollywood said Bake Off is going back to basics this year.
“We were getting a bit overcomplicated,” he said. “Sometimes it’s not just about the bakers in the tent, it’s about the people in the UK who watch the programme.
We want to encourage the viewers to bake.”