This Chocolate Eclair Cake features layers of graham crackers with homemade vanilla pudding lightened with homemade stabilized whipped cream, and topped with chocolate icing. A wonderful summer dessert!
Make the Pudding: Combine the sugar, cornstarch, and salt in a large saucepan. Whisk the milk into the sugar mixture until smooth and bring to a boil, scraping the bottom with a rubber spatula, over medium-high heat. Once the mixture reaches a boil, immediately reduce the heat to medium-low and cook, continuing to scrape the bottom, until thickened and large bubbles appear on the surface, 4 to 6 minutes. Remove the pan from the heat and whisk in the butter and vanilla extract. Transfer the pudding to a large bowl and place plastic wrap directly on the surface of the pudding. Refrigerate until cool, about 2 hours.
Make the Stabilized Whipped Cream: Stir the water and gelatin together in a bowl and let it sit until the gelatin softens, about 5 minutes. Microwave the mixture until it's bubbling around the edges and the gelatin dissolves, about 15 to 30 seconds. Using an electric mixer, whip the heavy cream on medium-low speed until foamy (about 1 minute). Then increase the speed to high and whip until soft peaks form, about 2 minutes. Add the gelatin mixture and whip until stiff peaks form, about 1 minute.
Assemble the Cake: Whisk one-third of the whipped cream into the chilled pudding, then gently fold in the remaining whipped cream, about a ¼ cup at a time, until combined.
Cover the bottom of a 9x13-inch baking with with a layer of graham crackers, breaking the crackers as necessary to line the bottom of the pan. Top with half of the pudding-whipped cream mixture (about 5½ cups), then another layer of graham crackers. Repeat with the remaining pudding mixture and another layer of graham crackers.
Make the Chocolate Glaze: Microwave the chocolate chips, heavy cream, and corn syrup in a medium bowl, stirring every 30 seconds, until smooth, 1 to 2 minutes total. Cool the glaze to room temperature, about 10 minutes. Cover the top layer of graham crackers with the glaze and refrigerate the cake for at least 6 hours before serving. Leftovers can be stored, covered, in the refrigerator, for up to 2 days.
Notes
If you do not want to use gelatin in the stabilized whipped cream, I've read that agar agar can be used as a substitute. I have not personally tried this, so I can't vouch for it in this recipe, but I would start there.
To freeze the chocolate eclair cake, refrigerate until the topping is set, then cover tightly with plastic wrap and again with foil, then freeze for up to 1 month.