1. Preheat your oven to 350°F and line a 9×5-inch loaf pan with parchment paper, leaving overhang on the long sides. Lightly grease the parchment with butter or cooking spray.

2. In a large mixing bowl, mash the very ripe bananas with a fork until mostly smooth with just a few small lumps. Add the melted butter, sugar, eggs, and vanilla extract, whisking together vigorously for about 30 seconds until smooth and creamy.

3. In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, and cream of tartar until everything is evenly distributed.

4. Add the dry ingredients to the wet ingredients all at once and use a wooden spoon or rubber spatula to gently fold everything together. Mix just until you don’t see any more streaks of dry flour. The batter should look thick, slightly lumpy, and rough, not smooth.

5. In a small bowl, mix together the 3 tablespoons of sugar and 1 tablespoon of cinnamon for the topping. Pour the batter into your prepared loaf pan and smooth the top gently with a spatula.

6. Brush the top of the unbaked batter generously with the 1 tablespoon of melted butter, making sure to cover the entire surface. Sprinkle the cinnamon-sugar mixture evenly over the buttered top, using all of it for that thick, crunchy crust.

7. Bake for 60-70 minutes, until the top is deeply golden brown with a gorgeous crackly crust and a toothpick inserted into the center comes out with just a few moist crumbs. The cinnamon-sugar topping will be caramelized and crispy.

8. Let the bread cool in the pan for about 15 minutes, then use the parchment overhang to carefully lift it onto a wire rack. Let it cool for at least 30 minutes before slicing.