In a medium saucepan, whisk together 1 cup (200 grams) sugar, flour, and salt. Slowly whisk in milk. Cook over medium heat, whisking constantly, until mixture is bubbly and thickened. Cook 2 minutes more.
Place egg yolks in a small bowl. Slowly drizzle about 1 cup hot milk mixture into egg yolks, whisking constantly. Pour egg mixture into remaining hot milk mixture in saucepan, and cook for 1 to 2 minutes, stirring constantly. Add butter and 1½ teaspoons (6 grams) vanilla, stirring until combined. Stir in coconut. Let cool at room temperature for 10 minutes.
Layer bananas in bottom of prepared Vanilla-Coconut Crust. Spoon filling over bananas. Cover with a piece of plastic wrap, pressing wrap directly onto surface of filling to prevent a skin from forming. Refrigerate for at least 4 hours. For best results, refrigerate overnight.
In the bowl of a stand mixer fitted with the whisk attachment, beat cream at medium speed until soft peaks form. Add remaining ¼ cup (50 grams) sugar and remaining 1 teaspoon (4 grams) vanilla, and beat until thickened and cloud-like. Dollop whipped cream onto filling, and top with banana slices, if desired.
Recipe by Bake from Scratch at https://staging.bakefromscratch.com/banana-coconut-cream-pie/