1. Place the milk, cornstarch, and sugar in a small saucepan and bring to a boil over medium, stirring constantly and scraping the bottom of the pan with a wooden spoon. Cook until mixture thickens, about 9 minutes, stirring constantly. Cook and stir 1 more minute. Whisk in the condensed milk and transfer to a bowl. Cover with plastic wrap and refrigerate for one hour or up to 24 hours.

2. Pour the heavy cream into the bowl of an electric mixer fitted with the whisk attachment. Beat on low until the cream thickens, then beat on high until it forms soft peaks. Add the milk mixture, vanilla extract, the vanilla seeds, and rum. Whisk on medium about 3 minutes or until mixture forms soft peaks.

3. In a 3 1/2-quart glass bowl with straight sides or a trifle dish, place one full layer of cookies, breaking them to fit and making sure they touch the sides of the bowl. (Do not overlap cookies.) Add one layer of banana slices, then one-fourth of the cream mixture. Continue layering cookies, bananas, and cream until you have four layers of each, ending with cream and swirling the top. (Save the remaining cookies for decorating.) Chill 1 hour, cover with plastic wrap, and refrigerate overnight .

4. Top with Sweetened Whipped Cream and reserved cookies (crumble if desired). Serve cold. Serves 10.

Sweetened Whipped Cream

1. Pour 1 cup cold heavy cream into the bowl of an electric mixer fitted with the whisk attachment. Add 1 tablespoon sugar and 1 teaspoon pure vanilla extract and beat on high until the cream forms soft peaks. Makes 2 cups.