I have been searching a LONG time and making MANY loaves of banana bread trying to find a light and fluffy (not dense and heavy) bread, and I finally found it! I think the sour cream has a lot to do with it. I have made 3 loaves, 2 of which turned out perfect, 1 of which didn't - I tried to cut back on the sugar and that must have been the problem. From now on I will follow the recipe exactly. I have not made it with the addition of the nuts yet. Don't be alarmed - the outside gets dark, but the inside is very moist. I use a 10" loaf pan and it bakes for exactly 50 minutes. BEWARE: The loaf will quickly disappear!