Malted Walnut Pie

Name: Malted Walnut Pie
Ingredients: 14 graham crackers (about 8 oz.); 2 tablespoons raw sugar or granulated sugar; 1 tablespoon all-purpose flour; ½ teaspoon kosher salt; 8 tablespoons (1 stick) unsalted butter, melted, slightly cooled; 2 cups walnuts; 4 oz. white chocolate, melted; 3 large eggs; ¾ cup light corn syrup; ⅔ cup (packed) light brown sugar; ¼ cup plus 2 Tbsp. barley malt syrup; ¼ cup malted milk powder; 1 tablespoon malt vinegar; ¾ teaspoon kosher salt; ½ teaspoon vanilla extract; ¼ cup (½ stick) unsalted butter; Unsweetened whipped cream (for serving; optional)