Preheat oven to 350 degrees F. Grease two 9 x 5 inch loaf pans and set aside
In a medium bowl, mix together the flour with the cinnamon, salt, and the baking soda
In a large bowl, cream the butter with the 2 cups of sugar. Mix in eggs, mashed bananas, sour cream and vanilla. Then mix in the flour
Pour the batter into the prepared pans
Bake for about 1 hour, or until a toothpick inserted in center comes out clean. Start checking for doneness at about 50-55 minutes