Preheat oven to 325°F (170°C).

In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar at medium-low speed just until combined; increase mixer speed to medium, and beat until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating until well combined after each addition and stopping to scrape sides of bowl. (Mixture may look a bit broken at this point, but batter will come together.)

In a large bowl, whisk together 1¾ cups (219 grams) flour, ground cereal, salt, and baking soda. In a medium bowl, whisk together sour cream, milk, and vanilla. With mixer on low speed, gradually add flour mixture to butter mixture alternately with sour cream mixture, beginning and ending with flour mixture, beating just until combined after each addition and stopping to scrape sides of bowl. Transfer half of batter (about 3 cups or 714 grams) to another medium bowl; add cinnamon, folding until well combined. Fold remaining 2 tablespoons (16 grams) flour into remaining batter in mixer bowl.

Spray a 10-cup Bundt pan* with baking spray with flour. Spoon and spread about one-third of plain batter (about 1 cup or 230 grams) in bottom of prepared pan; top with one-third of cinnamon batter (about 1 cup or 230 grams), spreading into an even layer. Repeat procedure twice with remaining batters. Tap pan on a kitchen towel-lined counter a few times to settle batter and release any air bubbles.

Bake for 45 minutes. Rotate pan, and cover with foil; bake until a wooden pick inserted near center comes out clean and an instant-read thermometer inserted near center registers at least 200°F (93°C), 15 to 20 minutes more. Let cool in pan for 10 minutes. Using a small offset spatula, loosen cake from center of pan. Invert cake onto a wire rack, and let cool completely.

Transfer cooled cake to a serving plate. Spoon Creamy Milk Glaze over and into grooves of cake. Garnish with cereal, if desired.