Preheat oven to 350 degrees. Line muffin pan with liners. Cream
the butter and sugar with a mixer. Add eggs and mix well.
Dissolve baking soda in the sour cream. Let it rise for minute,
then add it to the butter and egg mixture. Mix well with beater
on medium speed. Add bananas and blend in. Add flour and baking
powder . Mix in thoroughly, but no longer than necessary. Add
vanilla. Stir in chocolate chips by hand. Fill muffin cups. Bake
for 25 to 30 minutes. Recipe makes approximately 18 muffins.