Instructions

• Make the peanut butter pastry cream: In a medium heavy-bottomed saucepan, combine 2 cups half-and-half, 6 tablespoons of the ½ cup granulated sugar (reserve the remaining 2 tablespoons for the yolks), and a pinch of salt. Heat over medium, stirring occasionally, until the mixture reaches a full simmer (small bubbles form at the edges).
• While the half-and-half heats, whisk 5 egg yolks in a medium bowl until combined. Add the remaining 2 tablespoons granulated sugar and whisk until the sugar begins to dissolve and the mixture is slightly creamy (about 15 seconds). Whisk in 3 tablespoons cornstarch until smooth and pale yellow.
• Temper the yolks: with the mixer whisking, slowly whisk some of the hot half-and-half into the yolk mixture to warm it (a little at a time). Then scrape the yolk mixture back into the saucepan. Return the pan to medium heat and whisk constantly until the mixture comes to a simmer and thickens and becomes glossy (a few surface bubbles will burst), about 30 seconds.
• Off the heat, whisk in 1/4 cup cold unsalted butter (cut into 4 pieces) and 1½ teaspoons vanilla extract until smooth. Strain the pastry cream through a fine-mesh sieve into a medium bowl, then whisk in 3/4 cup creamy peanut butter until fully combined and smooth. Press plastic wrap directly onto the surface to prevent a skin, then refrigerate until cold and set, at least 3 hours or up to 2 days.
• Make the pretzel crust: Preheat the oven to 350°F (175°C). In a medium bowl, combine 1½ cups crushed pretzels and 1/3 cup granulated sugar. Pour 9 tablespoons melted unsalted butter over the pretzel mixture and stir with a fork until evenly moistened. Press the mixture firmly and evenly into a 9-inch pie pan, covering the bottom and up the sides. Bake 10–12 minutes, until lightly browned. Transfer to a wire rack and cool completely.
• Make the chocolate ganache: Put 3 ounces finely chopped semisweet chocolate in a medium bowl. Heat 1/4 cup unsalted butter and 1/4 cup heavy cream together until hot and just bubbling (microwave ~1 minute or heat in a small saucepan). Pour the hot butter-cream mixture over the chocolate, let sit 30–60 seconds, then stir until smooth. Whisk in 1/2 teaspoon vanilla and 1 tablespoon powdered sugar until fully incorporated and glossy.
• Pour the warm ganache over the cooled pretzel crust and spread to the edges. Refrigerate the crust with ganache for about 30 minutes, or until the ganache is set.
• Arrange the bananas: Place the 2 bananas (sliced about 1/2-inch thick) in a single layer over the set ganache.
• Finish assembling: Remove the chilled peanut butter pastry cream from the refrigerator; if very firm, whisk briefly to loosen. Spread the pastry cream evenly over the banana layer.
• Make the whipped topping: In the bowl of a stand mixer fitted with the whisk attachment (or using a hand mixer and a large bowl), combine 1½ cups heavy cream, 4½ teaspoons granulated sugar, and 1 teaspoon vanilla extract. Whip on medium speed until soft peaks form, about 3–4 minutes. Spread the whipped cream evenly over the pastry cream.
• Garnish and store: Garnish with crushed pretzels, chocolate, and peanut butter if desired. Cover leftover pie with plastic wrap and refrigerate for up to 2 days.