Measure flour, 1 cup sugar, baking powder,
baking soda, 1 1/2 teaspoons cinnamon, salt, buttermilk, oil, eggs
and vanilla into large mixing bowl. Beat 3 minutes. Pour into
prepared loaf pan. Smooth top.
Combine 2 tablespoons white sugar, 1 teaspoon
cinnamon and butter, mixing until crumbly. Sprinkle topping over
smoothed batter. Using knife, cut in a light swirling motion to
give a marbled effect.