1¾ cups (420 grams) whole milk, plus more if necessary1 cup (40 grams) crushed orange sweetened 3-grain O-shaped apple-and-cinnamon cereal* (see Notes)1½ cups (300 grams) granulated sugar5 large eggs (250 grams), room temperature1 tablespoon (13 grams) vanilla extract2 cups (250 grams) cake flour1 tablespoon (15 grams) baking powder1½ teaspoons (3 grams) apple pie spice½ teaspoon (1.5 grams) kosher salt½ cup (25 grams) finely crushed sweetened 3-grain O-shaped apple-and-cinnamon cereal1 (14-ounce) can (397 grams) sweetened condensed milk1 (12-ounce) can (354 grams) evaporated milkApple-Cinnamon Cereal Whipped Topping (recipe follows)Garnish: sweetened 3-grain O-shaped apple-and-cinnamon cereal
In a small bowl, combine milk and orange cereal. Refrigerate for 2 hours or up to overnight. Let come to room temperature before using.
Preheat oven to 350°F (180°C). Spray a 13×9-inch baking dish with baking spray with flour.
In the bowl of a stand mixer fitted with the whisk attachment, beat sugar and eggs at medium-high speed until pale yellow and doubled in size. Beat in vanilla.
Strain cereal milk through a fine-mesh sieve, discarding solids.
In a medium bowl, whisk together flour, baking powder, pie spice, and salt. With mixer on low speed, gradually add flour mixture to sugar mixture alternately with ¾ cup (180 grams) cereal milk, beginning and ending with flour mixture, beating just until combined after each addition. Fold in finely crushed cereal. Pour batter into prepared pan.
Bake until a wooden pick inserted in center comes out clean, 25 to 30 minutes.
In another medium bowl, combine condensed milk, evaporated milk, and remaining 1 cup (240 grams) cereal milk. (See Notes.)
Using a fork, poke holes all over warm cake; slowly pour milk mixture over cake. Let cool completely. Refrigerate for at least 3 hours. Just before serving, spread Apple-Cinnamon Cereal Whipped Topping on top, swirling as desired, and garnish with cereal, if desired.
*We used Kellogg’s Apple Jacks Cereal.
Notes: You must use just the orange cereal rings to soak in the milk for the cake and the cream for the Apple-Cinnamon Cereal Whipped Topping; otherwise, the milk and cream turn an unappetizing color.
If you don’t have 1 cup (240 grams) cereal milk left to soak the cake, add whole milk until you have 1 cup.