Oatmeal Pancakes

8 Tbs. (1 stick) unsalted butter, at room temperature 

2 tsp. ground cinnamon 

1 cup all-purpose flour 

1/2 cup cake flour 

1/2 cup quick-cooking rolled oats 

3 Tbs. sugar 

2 tsp. baking powder 

1 tsp. baking soda 

1/4 tsp. salt 

2 eggs 

2 1/2 cups buttermilk 

5 Tbs. unsalted butter, melted, plus more for cooking 

1 cup walnut pieces, toasted and chopped 

2 bananas, peeled and thinly sliced 

1/2 cup dried currants 

2 cups maple syrup, heated