Preheat oven to 375°F. Mix wheat flour, white flour, baking soda and salt together in a medium bowl. Work butter into mixture with your fingers.

Form a well in the middle of flour mixture and pour buttermilk into the well. Form your hand into a rigid claw and stir dough slowly but steadily in a spiral motion, starting in the middle and working outwards. Dough should be soft but not too wet or sticky. (Start with 1 3/4 cups buttermilk, gradually adding, if necessary, to achieve the right consistency.)

Turn dough out onto a floured board. Flour your hands lightly, then shape dough into a flat rectangle about 2 inches high. Cut dough in half lengthwise with a wet knife, then gently push each half into a lightly greased glass or foil loaf pan. Bake for 50 to 60 minutes, or until the tops of the loaves are nicely browned. 

Serve this bread with plenty of Kerrygold Irish Butter.