No doubt about it: toasted walnut oil will make the cake taste fantastic. But also no doubt about it: toasted walnut oil is pricey. What’s more, it can go bad quickly. Check out online suppliers for good prices. Open the can or jar, rub a little of the oil in your palm, and smell it to make sure it’s not rancid. If so, send it back for a full refund— or take it back to the store! And after the can or jar is opened, store it in the fridge for about a month, using it to make scrambled eggs divine or to drizzle over chopped vegetable salads.
For the cake
7 large tart apples, such as Granny Smith or Empire, peeled, cored, and chopped
1¾ cups plus 1 tablespoon granulated white sugar
¾ cup toasted walnut oil, plus additional for the sheet pan
3⅔ cups all-purpose flour
1¼ teaspoons baking powder
1 teaspoon ground cinnamon
½ teaspoon baking soda
½ teaspoon salt
2 large eggs plus 1 large egg white, at room temperature
2 teaspoons vanilla extract
3 cups walnut pieces
1. Stir the apples and sugar in a large bowl until well coated. Set aside at room temperature for 30 minutes to macerate, stirring occasionally.
2. Position the rack in the center of the oven. Heat the oven to 350°F. Generously oil the inside of a 13 × 18-inch lipped sheet pan.
3. Whisk the flour, baking powder, cinnamon, baking soda, and salt in a medium bowl until uniform.
4. Using a wooden spoon, stir the eggs, egg white, and vanilla into the apple mixture until smooth, then stir in the walnut oil until well combined.
5. Add the flour mixture and stir just until there are no dry bits of flour. The batter will be very thick. Using an offset spatula, spread the batter evenly into the prepared pan.
6. Bake until lightly browned and set and a toothpick or cake tester inserted into the center of the cake comes out clean, 23 to 25 minutes. Maintain the oven’s temperature. Cool in the pan on a wire rack until room temperature, about 1½ hours.
7. As the cake cools, spread the walnut pieces on a second large lipped sheet pan. Bake until fragrant and lightly browned, stirring occasionally, about 6 minutes. Cool in the pan to room temperature, about 1 hour.
For the glaze
9 tablespoons water
3 tablespoons light corn syrup
1 tablespoon vanilla extract
4 to 5 cups confectioners’ sugar
1. Mix the water and corn syrup in a large saucepan and bring to a boil over medium-high heat, stirring occasionally. Boil for 1 minute. Remove from the heat and stir in the vanilla.
2. Stir in 3½ cups of the confectioners’ sugar until smooth. Then continue adding more confectioners’ sugar in ¼-cup increments until the glaze is spreadable but not as thick as a standard frosting, like a cross between a drizzle and a frosting.
3. Drizzle and spread this mixture over the cake while still hot. Sprinkle the toasted walnuts over the top and press down gently with the back of a wooden spoon so they adhere.
TESTER NOTES
The apples will continue to macerate in the sugar even after baking, leading to a gummy cake by the next day. You’ll just need to eat this one up the day you make it!
