Preheat oven to 350°F. Line a loaf pan with parchment, spray, and set aside.
In a bowl, beat butter and brown sugar on low speed until blended.
Add eggs one at a time, mixing after each.
Add mashed bananas and vanilla, mix just until combined.
Add self rising flour; stir just until no dry flour remains.
Fold in chopped nuts, if using.
Pour batter into prepared pan and smooth the top.
Bake 60 minutes or until a wooden pick comes out clean.
Let cool in pan 5 minutes, then transfer to a wire rack.
Cool completely before slicing. Store airtight.
