Ingredients

• 4 cups all-purpose flour (plus an extra 1/4 cup for dusting)
• 1/4 cup granulated sugar
• 1 teaspoon sea salt
• 1 teaspoon baking soda
• 6 tablespoons cold unsalted butter (plus 1/2 tablespoon to grease the pan)
• 1 3/4 cups cold low-fat buttermilk (or kefir)
• 1 large cold egg
• 1 cup raisins or dried cranberries (optional)

Instructions

1. Preheat your oven to 375°F (190°C). Generously grease a 10-inch cast-iron skillet with 1/2 tablespoon of butter.
2. In a large mixing bowl, whisk together the flour, sugar, salt, and baking soda. Cut the cold butter into small cubes, then use your fingers to rub the butter into the flour mixture until it resembles coarse crumbs. If you're adding raisins or dried cranberries, stir them in now, breaking up any clumps of fruit.
3. Create a well in the center of the dry ingredients. In a separate measuring cup, whisk together the cold buttermilk (or kefir) and egg. Pour this liquid mixture into the dry ingredients and stir with a wooden spoon just until the dough is lightly moistened and begins to come together.
4. Turn the dough out onto a floured surface. Gently shape the dough into a round loaf, making sure not to overwork it. If the dough is too sticky, dust it lightly with flour. The dough should be shaggy and not perfectly smooth.
5. Transfer the dough to the greased skillet. Using a knife, score the top of the loaf with a deep "X" to help it bake evenly. Place the skillet in the preheated oven and bake for 50-55 minutes. The bread is done when it sounds hollow when tapped on the bottom.
6. Let the bread cool on a wire rack. Enjoy within two days, or store leftovers in the refrigerator for up to a week.