How to Make It
In a small bowl, whisk the cornstarch with 1/2 cup of water. In a medium saucepan, combine the sugar, corn syrup and salt with 1 1/2 cups of water and bring to a boil. Whisk in the cocoa powder, then whisk in the cornstarch slurry and cook until thick, about 1 minute. Remove from the heat and whisk in the chocolate and butter until smooth. Scrape the pudding into a bowl and press a piece of plastic wrap directly on the surface. Let cool, then refrigerate until chilled, about 1 hour.
In a bowl, toss the crushed graham crackers with the butter, honey, cinnamon and salt until evenly moistened.
In a large bowl, using a hand mixer, beat the cream with the sugar, mashed banana and vanilla seeds to stiff peaks.
Spoon the pudding into six 8-ounce jars or cups. Top with a sprinkling of the graham cracker crumbs, a layer of sliced bananas and a scoop of ice cream. Garnish the parfaits with a dollop of the banana cream and graham cracker crumbs and serve.