She left The Great British Bake Off last year after the show moved from the BBC to Channel 4.
Britain's Best Cook will air on BBC One and be presented by Strictly Come Dancing presenter Claudia Winkleman.
Claudia said, "I am over the moon to be part of this show".
Ten contestants will compete in Britain's Best Cook, which will last for eight episodes.
It's thought that both new and more traditional recipes will be used on the programme.
Mary Berry says, "This series is going to encourage proper home cooking".
A second judge will join Mary but we don't know who that is yet.
Mary Berry is back to judge a brand new cooking contest called Britain's Best Cook.