Banana Sour Cream Blueberry Bread

Bread:
(Dust pans lightly with this mixture.)
1/4 c. sugar
1 tsp cinnamon

In a large bowl, cream together:
3/4 c. butter
3 c. sugar
3 eggs
6 very ripe banana's mashed
1 - 16 oz container sour cream
2 tsp vanilla
2 tsp ground cinnamon
1/2 tsp salt
3 tsp baking soda
4 1/2 c. flour
1 c. chopped walnuts (optional)
1 1/2 c. blueberries (I use frozen)

Crumb Topping:
1 c. brown sugar
1/4 c. butter, diced
1 c. flour

For topping, in a medium bowl, mix together the sugar and flour. Mix in butter with a fork or stand mixer just until the topping is crumbly. Top bread before baking. You will have enough for 4 loafs of banana bread, and will have some leftover. I store the leftover in the freezer.

Preheat oven to 300 degrees. Grease four 7x3 in. loaf pans. Divide batter among prepared pans. Top with crumb mixture. Bake for 1 hour, until toothpick inserted in center comes out clean. Run knife along sides of pan and dump bread out to cool.