Preheat the oven to 375 degrees F.

Place the raisins in a bowl and cover with 1 cup boiling water. Let sit and rehydrate for 10 minutes, then drain well in a sieve.

Into a large bowl sift together the flour, whole wheat flour, baking powder, baking soda and salt. Add the butter into the dry ingredients and work with your fingertips until it resembles dry crumbs. Add the caraway seeds, treacle, buttermilk and raisins and work with your fingers until just mixed and a wet dough is formed, being careful not to over mix. Place the dough on a lightly floured surface and form into a round. Press down on the dough with the palm of your hand and press to form a flat round about 1 1/2-inches high.

With a knife, cut a 1/4-inch deep cross in the center of the dough. With a pastry brush paint the dough with the cream and sprinkle the top with the oats. Place on a baking sheet and bake until light brown and cooked through, about 30 to 40 minutes.

Remove from the oven and cool slightly on a wire rack before slicing. Serve warm with plenty of sweet butter.