Sour cream cake bread

Why call it cake bread? Well, take a close look at the texture of the bread, doesn't it look so soft and fluffy, almost like a cake?
The original recipe is found on allrecipes website, it listed to use 1pack(2-1/4tsp) of yeast, but guess what? Careless people like me won't read recipe properly, and I ended up using only 1tsp, which is like less than half. However, mistake didn't stop me halfway, i decided to let the dough rise for a few more hours and WaLaa it went up highly and came out super soft. Also, thanks to a special ingredient to achieve this lovely soft texture, which you can already figure it out by the title, yes it is Sour Cream!

Sour cream cake bread Recipe (make one 9inch cake pan, or 10 rolls)
3 1/4cups flour
2 1/4tsp instant yeast (used only 1tsp)
3 tbsp brown sugar (used white sugar)
1/2tsp salt
1/2cup skim milk (i used warm water)
3/4cup low fat sour cream (used 1/2cup)
2 egg whites (used 1 whole egg)
1tbsp vanilla (used 1tsp)