In a large mixing bowl, mash bananas on low-medium speed using a mixer or with a fork/masher.
Mix in butter and sugar. Add one egg at a time, vanilla extract, and mix until fully blended.
Add all dry ingredients, mix until fully blended.
In a separate mixing bowl, toss cranberries in 1 Tbsp of flour so they are lightly coated. Fold cranberries into the batter. This step prevents the berries from sinking to the bottom of the loaf when baking.
Pour batter into a lightly greased loaf pan.
Bake at 350 F for 50 minutes to 1 hour until inserts in the centre of the loaf comes out clean.