Preparation Preheat oven to 325°F. Butter and flour springform pan. Combine 1/4 cup flour, 1/4 cup sugar, and 2 tablespoons butter in a small bowl. Using your fingertips, rub together until mixture is crumbly; set topping aside. Sift remaining 2 cups flour, baking soda, and next 5 ingredients into a large bowl. Using an electric mixer at low speed, beat 1 cup butter, 1 cup sugar, and sorghum in another large bowl, occasionally scraping down sides, until smooth, 2-3 minutes. Add eggs; beat until light and fluffy, 3-4 minutes. Beat in flour mixture in 3 additions, alternating with buttermilk in 2 additions, beginning and ending with dry ingredients. Pour batter into prepared pan. Bake cake until top looks just set, about 40 minutes. Immediately sprinkle topping over cake; bake until a tester comes out clean when inserted into center, 25-30 minutes longer. Transfer to a wire rack and let cake cool in pan. Remove pan sides. Cut into wedges; serve with ice cream.
Preparation Preheat oven to 325°F. Butter and flour springform pan. Combine 1/4 cup flour, 1/4 cup sugar, and 2 tablespoons butter in a small bowl. Using your fingertips, rub together until mixture is crumbly; set topping aside. Sift remaining 2 cups flour, baking soda, and next 5 ingredients into a large bowl. Using an electric mixer at low speed, beat 1 cup butter, 1 cup sugar, and sorghum in another large bowl, occasionally scraping down sides, until smooth, 2-3 minutes. Add eggs; beat until light and fluffy, 3-4 minutes. Beat in flour mixture in 3 additions, alternating with buttermilk in 2 additions, beginning and ending with dry ingredients. Pour batter into prepared pan. Bake cake until top looks just set, about 40 minutes. Immediately sprinkle topping over cake; bake until a tester comes out clean when inserted into center, 25-30 minutes longer. Transfer to a wire rack and let cake cool in pan. Remove pan sides. Cut into wedges; serve with ice cream.