For decades, I assumed the cross my Irish grandmother cut into the top of her round loaves of soda bread in her upstate New York farmhouse was a traditional blessing. It was a natural conclusion since her bread was as soul-sustaining as communion at an Irish Catholic mass. So I was astounded to learn that the bread cross had a far more ancient – and superstitious – purpose.
When I asked master baker Mary Gleeson, co-owner of Gleesons Restaurant & Rooms in the Irish town of Roscommon about the cross tradition, she answered without hesitation: “You have to cut a cross in the dough to let the fairies out.”
“What happens if you don’t?” I asked.
“I don’t know, we’re scared not to,” she replied, followed by a self-conscious giggle.
http://www.bbc.com/travel/story/20160920-secrets-of-the-soda-bread-masters
Lots of good tips there, including a recipe that looks like it could double for cannonballs come the revolution.
Aerating the flour is good. I found that putting flour, salt and baking powder into the Kitchen Aid and running to mixer for a few seconds to combine them worked. US buttermilk is cultured and quite thick, so you don't need to let it sit around for a week to thicken. And my own recipe, which duplicated soda bread baked by a convent in Boston, uses what I call a big handful of dried currants and a small handful of caraway. I know it's imprecise, but it works.
And don't forget to let the fairies out. You get a crisper crust that way.