Stir breadcrumbs, sugars, pecans, spices, 4 tablespoons butter, and vanilla bean paste with a fork in a large bowl to make a crumb.
Grease pie plate with 1 tablespoon of melted butter.
Stir together the sliced bananas, bitters, brown sugar, spice, cornstarch, and vanilla bean paste in a medium bowl.
Arrange half of banana mixture in the pie plate.
Sprinkle half of the crumb over the bananas.
Repeat, making another layer of bananas and another layer of crumb.
Bake for 40 minutes, until slightly browned.
Notes
To make fresh breadcrumbs, allow a loaf of bread to become stale by leaving it sit out overnight. If it's sliced, separate the slices slightly to allow for airflow between them. If it's not sliced, cut it into thick slices with a bread knife. In the morning, when the bread has become a little crunchy, place all the bread into a food processor and pulse until crumbs have formed. Measure the breadcrumbs after removing them from the food processor.Nutritional information does not include ice cream.