Preheat oven to 350 deg. F
1/2 cup plain yogurt OR sour cream OR real mayonnaise
1 1/3 cups mashed banana (about 3)
1 1/2 cups flour
1 cup sugar
1 tsp baking soda
1 tsp salt
1/2 cup chocolate chips, melted
Mix all ingredients together except chocolate.
Put half of dough into a small bowl and add chocolate to this.
Grease or line with parchment an 8 inch x 4 inch loaf pan.
Put spoonfuls of each dough alternately in pan.
Swirl a knife gently through doughs.
Bake for one hour and five minutes.
Cool in pan for ten minutes before removing from pan.