Preheat oven to 350°F.

Butter and flour a 9x5" loaf pan or 8" round cake pan.

Chop walnuts and toss with 2 tablespoons of flour.

Sift flour, baking soda, baking powder, cinnamon, and salt.

Combine mashed bananas and orange juice.

In a stand mixer, beat eggs, sugar, oil, sour cream, and orange zest on medium-high for 2-3 minutes.

Stir in banana mixture and beat for 1 more minute.

Add flour mixture on low speed until just combined.

Stir in floured walnuts with a wooden spoon.

Pour into prepared pan and shake gently.

Bake for 50-55 minutes at 350°F on lower rack.

Cool in pan on wire rack for 10 minutes.

Remove from pan and cool completely on rack.

For glaze: Combine all glaze ingredients except butter and vanilla in a saucepan.

Cook on medium heat for 3-4 minutes.

Cover pan, raise heat, and boil for 3 minutes.

Uncover, reduce heat to medium, and cook without stirring, swirling pan until honey-like thickness, about 5-7 minutes.

Remove from heat and add butter and vanilla.

Cool completely and spread on cake.