This famous, hearty Irish bread gets its rise from soda—but not the kind you drink!
Adjust oven rack to lower-middle position and heat oven to 400 degrees. Line rimmed baking sheet with parchment paper.
In large bowl, whisk all-purpose flour, whole-wheat flour, wheat germ, sugar, salt, baking powder, and baking soda until combined.
In liquid measuring cup, use fork to stir buttermilk and melted butter until butter forms small clumps.
Add buttermilk mixture to bowl with flour mixture. Use rubber spatula to stir until dough comes together.
Sprinkle clean counter lightly with extra flour. Transfer dough to counter and use your floured hands to knead until smooth ball forms, about 30 seconds.
Pat and shape dough into 7-inch circle. Use paring knife to cut cross into top of loaf.