Preheat the oven to 425 degrees.  Grease the bottom and about 1-inch up the side of your Dutch oven with the butter and dust with flour.  Shake out any excess flour. Set aside.

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

Make a well in the center of the dry ingredients and pour the baking soda into it.

Stir the buttermilk and dry ingredients together until a sticky dough forms.

Turn the dough out onto a lightly floured board and gently knead the dough for about a minute to smooth out the dough.  

Shape the dough into a round disk that will fit into the bottom of your Dutch oven.

Place the dough in the Dutch oven. 

Wet your hands and smooth out the top of your loaf.

Use a sharp knife to cut two slashes into the top of the dough.

Place the lid on the Dutch oven and bake the bread for 30 minutes.

Remove the lid from the pot and continue to bake the bread for another 15 minutes.

The bread is done when it is golden brown and sounds hollow when you tap it.

Remove the bread from the oven and gently turn your loaf out onto a wire rack to cool.

Cover the bread with a dish towel to keep it moist.