Preheat the oven to 375°F.
In a large bowl, whisk together the flour, baking soda and salt.
Add the buttermilk and 2 tablespoons melted butter and mix just until combined.
Generously flour your work surface. Scrape the dough onto your work surface then sprinkle the top of it with additional flour. With very light pressure, turn the dough so that it is coated on all sides with flour then knead it a maximum of eight times. Shape it into a 6-inch domed round.
Transfer the dough to a nonstick baking sheet or a baking sheet lined with parchment paper.
Using a sharp knife, cut a large "X" across the top then brush the top with the remaining 1 tablespoon melted butter.
Bake the bread for about 35 minutes or until it is no longer doughy in the center. Remove it from the oven and set it aside to cool before slicing and serving.