Preheat oven to 375F/190C, line a baking sheet with parchment paper.
In a small bowl soak the raisins in boiling water for 10-15 minutes then drain and towel dry.
In a small bowl mix the discard and buttermilk.
In a large bowl whisk together the flour, sugar, baking soda, salt and raisins. Then add the discard and combine with a fork until almost combined.
Move to a lightly floured flat surface and gently knead a few times to bring the dough together, form into an oval shape and place on the prepared baking sheet, score the dough with a deep cross with a sharp knife.
Bake 30-40 minutes until baked through. Move to a wire rack and let cool before serving. Enjoy!
Notes
Lievito madre discard may bring a milk tangy flavour that complements the buttermilk. It also helps make the crumb more tender.
To make homemade buttermilk
Combine 2½ tablespoons cream (whole, heavy or whipping cream), 9 tablespoons milk (2% or whole milk) and ½ tablespoon of vinegar or lemon juice. Let sit 15 minutes before using.
How to store the soda bread
Store: As with most quick breads, this tastes best served the same day it is made. You can store leftover Irish sourdough soda bread in an airtight container at room temperature for 2-3 days.Freeze: To store longer than a few days, I like to freeze it in slices for up to 3 months. Wrap slices in plastic wrap then foil and store in a freezer safe container. Thaw and reheat individual slices in the toaster or oven.