It’s a party: Rich vanilla cake layered with salted caramel ice cream, under a pillowy topping of whipped cream drizzled with caramel sauce. Serve this luscious ice cream cake at a birthday, or for a backyard BBQ on the muggiest of afternoons.
1Preheat the oven to 350°F. Butter a 9-by-13-inch baking dish, line it with parchment so it overhangs two sides, and butter the parchment.
2To make the cake, sift the flour and baking powder into a bowl. Whisk in the sugar and salt. In another bowl, whisk together 3⁄4 cup warm water, the egg, oil, and vanilla until blended. Pour the wet ingredients into the dry ingredients and stir just until blended. The batter will be very thick. Spread the batter into the prepared dish in an even layer. Bake until a toothpick inserted into the center of the cake comes out clean, about 20 minutes. Let cool for 10 minutes in the dish on a wire rack, then remove from the dish and let cool completely. Remove the parchment and return the cake to the dish.
3Put the ice cream in a bowl and stir with a large metal spoon to soften the ice cream until spreadable (make sure it doesn’t get overly soft and soupy). Spread the ice cream over the top of the cake into a thick, even layer. Cover with plastic wrap and freeze until firm, about 4 hours.
4In a bowl, using an electric mixer fitted with the whisk attachment, whip the cream, sugar and vanilla on medium speed until medium-stiff peaks form.
5Spread the whipped cream over the ice cream in an even layer. Drizzle with the caramel sauce. Cut into squares and serve.