Preheat oven to 350° F / 176° C.  Line a large rimmed baking tray with parchment.

In a large bowl, combine the whole wheat flour, all purpose flour, kosher salt, and baking soda.

Add the butter to flour bowl, using your hands or a bench scraper to work it into the dry ingredients.

Add the honey and the buttermilk, and use a bench scraper to combine.

With your hands or a bench scraper, work the mixed fruit into the dough.

Knead in about three quarters of the rolled oats, reserving the rest for coating the loaf.

Shape dough into a ball and roll in the remaining oats.

Transfer to prepared tray.

With a sharp knife or bread lame, cut a cross-shaped incision into the loaf.

With your fingertips, press down to increase the size of the opening.

Bake in preheated oven for 45 minutes, or until top and bottom are very deeply golden brown.

Transfer to wire rack to cool.

Slice with a serrated knife. Serve warm or at room temperature.