Preheat oven to 375 degrees.
In a large bowl by hand with a spoon, stir together the flour, baking soda, and salt.
Stir in the buttermilk and cranberries (or raisins) until a dough forms.
Turn the dough out onto a lightly floured surface and knead for 1 - 2 minutes. It should be soft and malleable but not overworked.
Pat into a 4-inch dough ball and place on the pan. Cut an X into the top with a serrated knife.
Bake 35-40 minutes or until golden brown. Cool completely before slicing.