Preheat your oven to 350°F (175°C).
Prepare the pie crust by combining flour, butter, sugar, and salt.
Press the crust mixture into a 9-inch pie pan evenly along the bottom and up the sides.
Bake the pie crust for 10-12 minutes until lightly golden.
In a bowl, mash the ripe bananas well, then stir in the sweetened condensed milk and vanilla extract.
Pour the banana mixture into the pre-baked crust, spreading it evenly.
In a separate bowl, combine crushed graham crackers, brown sugar, and cinnamon for the crumb topping.
Sprinkle the crumb mixture evenly over the banana filling.
Bake the pie for another 20-25 minutes, until the topping is golden brown.
Let the pie cool completely before slicing and serving.
