Grease a baking sheet or an 8- to 9-inch glass pie dish. If using a well-seasoned cast-iron skillet, you do not need to grease it. Preheat the oven to 400°F.
Place 1½ tablespoons of fresh lemon juice or vinegar in a measuring cup. Fill the cup with soy milk up to the 1½ cup mark. Set the mixture aside for a few minutes to thicken and curdle while you move onto the next step.
In a large bowl, use a fork to mix together the flour, baking soda, salt and, if using, caraway seeds and dried fruit.
If using orange zest, stir it into the thickened buttermilk. Stir the buttermilk into the dry ingredients until combined. The dough will be very sticky. Working quickly, turn the dough out onto a floured surface and knead only a few times to form a cohesive ball. Pat the ball into a round disk, about 6 inches in diameter and 1½ inches thick.
Place the dough disk on the baking sheet, pie dish or cast-iron skillet. With a sharp knife, score an X across the top, cutting into the dough about ½ inch deep.
Bake for 45 minutes, until the bread is golden brown and sounds hollow when tapped on the bottom. Turn the loaf out onto a cooling rack. Ideally, serve warm or toast slices the second day.