Preheat your oven to 425°F (220°C).

In a large bowl, mix together the flour, baking soda, salt, and sugar.

Make a well in the center and add the buttermilk and melted butter. Mix until a dough forms.

Turn the dough onto a floured surface and knead it gently for a minute.

Shape the dough into a round loaf and place it on a baking sheet lined with parchment paper.

Cut a deep cross into the top of the loaf with a sharp knife to help it rise.

Bake for 25–30 minutes or until the bread is golden brown and sounds hollow when tapped on the bottom.

Let it cool on a wire rack before slicing.