Add the flour, baking soda, salt, sugar, and nettle to a bowl and mix to combine.
In a separate bowl, mix together the milk and vinegar. Let it sit for a moment, then pour it into the bowl with the dry ingredients. Stir together til well combined.
Grease a small-medium cast iron pan. Pour the dough into the middle of the pan and use a spatula to form it into a loaf shape.
Bake at 375°F for about 25-30 minutes. The loaf is done when it starts turning golden brown and makes a distinctive thunk noise when you tap it.
