Step 1

Preheat oven to 350 degrees Fahrenheit or 175 degrees Celsius. Grease a 9*5 loaf pan or a 9 inch cake pan.

Step 2

Mix all purpose flour + salt + baking powder + baking soda + corn starch in a bowl and whisk well to combine.

Step 3

Beat butter by hand or with a hand mixer until soft. Add sugar and beat well until the mixture is soft and fluffy. Add eggs one by one and mix well after each addition. Add vanilla and mix well.

Step 4

Now add flour in three batches alternating with sour cream, beginning and ending with flour. Pour into the prepared pan.

Step 5

Add the topping ingredients in a bowl and mix well with a fork pressing in between. Spread this on the cake. Bake for 40-45 minutes or till a tooth pick inserted in the center of the cake comes out clean.