Preheat your oven to 350°F (175°C). In a food processor, crush the cornflakes until fine but still slightly textured. In a medium bowl, melt the butter and mix it with granulated sugar. Stir in the crushed cornflakes until evenly combined, then press firmly into a 9x13 inch baking dish. Bake for 12 minutes until golden brown, and bake the remaining cornflake crumbs for another 5 minutes before cooling them completely.

In a saucepan, bring the whole milk to a gentle simmer along with the scraped seeds from the vanilla bean. While it’s warming, vigorously whisk the egg yolks and additional sugar together until creamy. Gradually pour the warm milk mixture into the yolk mixture, whisking constantly to prevent curdling. Return the mixture to the heat, stirring until it thickens slightly, then incorporate dissolved gelatin. Chill in the fridge until completely cooled, around 2 hours.

Once the vanilla custard filling is cooled, it’s time to whip up the heavy cream. In a large mixing bowl, beat the heavy cream with powdered sugar until you reach stiff peaks. Gently fold the whipped cream into the cooled custard in thirds, ensuring a smooth and creamy texture for your Milk and Cereal Bars. Be careful not to deflate the whipped cream as you mix.

Spread the vanilla cream filling evenly over the cooled cornflake crust in the baking dish. Take the remaining cornflake crumbs and sprinkle them generously over the top, pressing down gently to adhere. Cover the baking dish with plastic wrap and chill in the refrigerator for at least 4 hours, or ideally overnight, to set the bars perfectly before slicing into squares.