crust:
1. Place a rack in lower third of oven and preheat to 350°.

2. Crumble the biscuits into the food processor, 1 Tbsp. light muscovado sugar and 1 tsp. flake salt and pulse until the biscuits are very finely ground, like sand.

3. Add 5 Tbsp. unsalted butter, melted, slightly cooled, and 1 tsp. vanilla bean paste or vanilla extract and pulse until the texture of wet sand.

4. Put the mixture into a 9" diameter metal or glass pie plate and press firmly and evenly up sides and across bottom with a flat-bottomed measuring cup (building the sides first, then smoothing the bottom will make for a more even crust). Chill crust in the refrigerator 20 minutes (or, if you are short on time, in the freezer 10 minutes).
Step 4
Place pie dish on a rimmed baking sheet if desired; bake crust until a deeper golden brown, 15–18 minutes. Let cool.
Do Ahead: Crust can be baked 2 days ahead. Store tightly wrapped at room temperature.


FILLING AND ASSEMBLY
Step 5
Scatter ½ cup coarsely chopped honey-roasted peanuts or salted roasted cashews in an even layer over crust and set aside.
Step 6
Combine ½ cup (100 g) granulated sugar and ¼ cup water in a medium saucepan, cover, and heat over medium (no need to stir) until sugar is dissolved and syrup is boiling, 4–7 minutes. Uncover and continue to cook syrup, stirring or swirling occasionally, until a deep brown color (you want caramel to be similar in color to the baked graham cracker crust), 10–15 minutes.
Step 7
Remove pan from heat; immediately add 4 Tbsp. unsalted butter, cut into pieces, room temperature, to caramel (be careful as mixture will foam vigorously). Using a heatproof rubber spatula, preferably one with a long handle if you’ve got it, stir vigorously until butter is melted (caramel may look broken or curdled at this point). Add ½ cup sweetened condensed milk and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt and stir until combined and smooth. Pour warm caramel over reserved nuts in crust, pushing carefully into an even layer with spatula as needed.
Step 8
Peel and slice 4–5 large ripe but firm bananas into ½"-thick rounds. Starting at the crust’s edges and working your way in, arrange over caramel (it’s okay if it is still slightly warm) in concentric, slightly overlapping rings. Chill pie while you make the topping.
Step 9
Using an electric mixer or stand mixer fitted with the whisk attachment, beat 1¼ cups heavy cream, ½ cup sour cream, 2 Tbsp. vanilla instant pudding mix, 1 tsp. vanilla bean paste or vanilla extract, remaining ¼ cup (50 g) granulated sugar, and remaining 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt in a medium bowl until firm peaks form, about 5 minutes.
Step 10
Using a small offset spatula, spread whipped cream mixture over pie, making sure to cover bananas completely and swirling to create dramatic peaks and swoops. Chill, uncovered, until caramel is set and pie is very cold, at least 2 hours and up to 4 hours.