MAKE PUDDING

1. Whisk together flour, salt, and 2/3-cup sugar in medium saucepan. Whisk in milk, egg yolks, and 1/2-cup cream. Cook over medium heat, whisking constantly, until thickened, 7 to 9 minutes. Remove from heat and whisk in peanut butter and 2 tsp vanilla.

ASSEMBLE DESSERT

1. Arrange 25 wafers in the bottom of an 8-by-8-inch glass baking pan. Pour in 1/3 of the pudding, covering the cookies as completely as possible. Top with half of banana slices, 1/4-cup peanuts, and remaining cookies. Check for evenness, gently pushing down on cookies as necessary. Whisk the pudding, making sure that any skin that may have formed on the top is fully incorporated back into the pudding, and that there are no lumps. Add another 1/3 of the pudding to the baking pan. Lay in remaining banana slices in a single layer – you’ll have some slices leftover. Slice the leftover banana slices into half-moons and snuggle them sideways along the perimeter of the pan, gently pushing them down so they don’t interfere with the evenness of the overall top layer. Add another 1/4 cup of nuts. Cover with remaining pudding. (If it has become too cool to pour, reheat it gently while whisking constantly.) Cover with plastic wrap, pushing the wrap right onto the surface of the pudding. Chill 4 hours or overnight.
2. Whisk remaining 3 Tbs sugar, 1 1/4-cups cream, and 1 tsp vanilla on medium-high with an electric mixer just until stiff peaks form, 2 to 3 minutes. Spread over top. Sprinkle with remaining 1/4-cup peanuts.