Crust:
Position a rack in the center of the oven and preheat to 350°. Lightly grease an 8-inch springform pan with cooking spray.
In a food processor, pulse the pecan shortbread cookies, raw pecans, brown sugar, and salt until coarse crumbs form. Add melted butter and pulse until mixture resembles damp sand.
Press crumb mixture into bottom and sides of prepared pan.
Bake crust for 10 to 12 minutes until fragrant and slightly darker. Cool.

Cheesecake:
Lower oven to 325°. Prepare simmering water bath.
In mixer, beat mashed bananas, brown sugar, cinnamon, and salt on low until combined.
Add cream cheese, beat on medium speed until smooth.
Add eggs one at a time, beating on low, scraping bowl each time. Stir in vanilla just until combined.
Wrap springform pan with two sheets of foil to create water-tight seal.
Pour filling into crust.
Place pan in roasting pan. Add simmering water halfway up springform pan sides.
Bake cheesecake 70 to 85 minutes until edges set and center jiggles slightly.
Cool in water bath 1 hour, then to room temperature. Refrigerate 4 hours or overnight.

Topping:
Heat butter and brown sugar in skillet over medium until butter melts and sugar dissolves.
Remove from heat, stir in cinnamon.
Add banana slices in single layer, cook without stirring 1 minute.
Flip slices, add splash of water to deglaze. Simmer 2 to 3 minutes until sauce thickens.
Cool topping at least 15 minutes.
Remove springform sides, spoon topping evenly over cheesecake before serving.