Roast the banana (optional): Place the very ripe banana, unpeeled, on a baking sheet. Bake at 350°F (175°C) for 15–20 minutes until blackened and fragrant. Cool, peel, and mash.

Make the pudding: In a saucepan, whisk milk, cream, sugars, cornstarch, egg yolks, and salt. Cook over medium heat, whisking, until thick bubbles form, 6–8 minutes. Remove from heat; whisk in butter, vanilla, and the mashed roasted banana.

Cool it fast: Pour pudding into a shallow dish. Press plastic wrap directly on the surface to prevent skin. Chill 30–45 minutes until slightly warm, not hot.

Prep the cookies: Lightly toast shortbread or Biscoff crumbs in a dry skillet over medium heat for 2–3 minutes. Let cool. Keep wafers whole for layering.

Slice bananas: Toss fresh slices with a splash of lemon juice if you want to slow browning. Pat dry.

Whip the topping: Beat cream, powdered sugar, and vanilla to soft peaks. Fold in Greek yogurt until smooth and glossy.

Layer it up: In a 9x9-inch dish or trifle bowl, add a layer of wafers. Spoon on a third of the pudding. Add banana slices, a sprinkle of toasted crumbs and pecans, and a light drizzle of caramel. Repeat two more times.

Top and chill: Spread the cream topping over the final layer. Add a final scatter of crumbs and a few wafer halves for looks.

Rest: Cover and chill at least 4 hours, ideally overnight. This sets the layers and lets flavors meld.