Preheat the oven: Set your oven to 375°F (190°C). Line a baking sheet with parchment paper or lightly grease it.
Mix the dry ingredients: In a large bowl, whisk together the gluten-free flour, baking soda, salt, and sugar. Add the raisins or currants if using, tossing them to coat.
Prepare the wet ingredients: In a separate bowl, combine the buttermilk and melted butter. If using a dairy-free milk alternative, let it sit for a few minutes to curdle.
Combine the dough: Slowly pour the wet ingredients into the dry ingredients. Stir gently until a sticky dough forms. Do not overmix.
Shape the bread: Turn the dough onto a lightly floured surface (using gluten-free flour) and shape it into a round loaf. Transfer to your prepared baking sheet.
Score the top: Using a sharp knife, cut a deep cross on top of the loaf. This helps it bake evenly and gives it the iconic soda bread look.
Bake: Place the loaf in the oven and bake for 35-40 minutes, or until golden brown and hollow-sounding when tapped on the bottom.
Cool and serve: Allow the bread to cool on a wire rack for at least 15 minutes before slicing. Serve warm with butter, jam, or alongside your favorite Irish dishes.