Preheat oven to 375°F. Spray 8-inch-diameter cake pan with nonstick spray. Whisk flour, 4 tablespoons sugar, baking powder, salt, and baking soda in large bowl to blend. Add butter. Using fingertips, rub in until coarse meal forms. Make well in center of flour mixture. Add buttermilk. Gradually stir dry ingredients into milk to blend. Mix in raisins.
Using floured hands, shape dough into ball. Transfer to prepared pan and flatten slightly (dough will not come to edges of pan). Sprinkle dough with remaining 1 tablespoon sugar.
Bake bread until brown and tester inserted into center comes out clean, about 40 minutes. Cool bread in pan 10 minutes. Transfer to rack. Serve warm or at room temperature.