Preheat oven: Preheat your oven to 425°F (220°C). Lightly dust a baking sheet with flour or line it with parchment paper.
Combine dry ingredients: In a large mixing bowl, whisk together the flour, baking soda, and salt.
Add buttermilk: Make a well in the center of the dry ingredients and pour in the buttermilk. Stir the buttermilk into the flour mixture until just combined; the dough should be soft but not too wet or sticky.
Knead dough: Turn the dough out onto a lightly floured surface. Gently knead it a few times to bring it together into a round loaf. Be careful not to over-knead.
Shape and score: Place the dough on the prepared baking sheet and use a sharp knife to cut a deep X into the top, about an inch deep.
Bake: Bake in the preheated oven for about 30-40 minutes, or until the bread is golden brown and sounds hollow when tapped on the bottom.
Cool and serve: Remove the loaf from the oven and let it cool on a wire rack for at least 10 minutes before slicing. Best served warm.