For the crust: In a food processor, pulse the HighKey Vanilla Wafers until fine crumbs. Add the melted butter and pulse until well combined. Press firmly into the bottom of an 8x8 inch pan lined with parchment paper. Refrigerate while you make the filling.

For the chocolate layer: In a small saucepan, heat 1/2 cup heavy whipping cream over medium heat until simmering. Remove from heat and stir in the sugar-free chocolate chips until melted and smooth. Pour this chocolate ganache over the chilled crust and return to the refrigerator.

For the banana custard filling: In a medium saucepan, whisk together the unsweetened almond milk, remaining 1/2 cup heavy whipping cream, and egg yolks. Heat over medium-low heat, whisking constantly, until the mixture thickens enough to coat the back of a spoon (about 8-10 minutes). Do not boil.

Remove from heat and whisk in the Swerve Confectioners, allulose, and banana extract until fully dissolved and smooth. Let cool slightly, then pour over the chocolate layer in the pan. Cover loosely with plastic wrap, pressing it directly onto the surface of the custard to prevent a skin from forming.

Refrigerate for at least 4 hours, or preferably overnight, until thoroughly chilled and set. Once set, lift the bars out of the pan using the parchment paper.

Slice into bars and serve. Garnish with additional whipped cream or sugar-free chocolate shavings if desired.