1-First Step: Preheat your oven to 350°F (325°F for dark or nonstick pans). Grease a 10-12 cup bundt pan thoroughly with solid shortening, reaching every crevice. Dust with 2 tbsp flour or cocoa powder, tapping out the excess for flawless release.

2-Second Step: Crush 20 Oreo cookies. Measure 1 1/2 cups crushed Oreos for the batter and reserve 1/2 cup for topping. Soften cream cheese if using the optional filling. Have all other ingredients at room temperature.

3-Third Step: In a large bowl, combine the chocolate cake mix, instant vanilla pudding mix, 4 large eggs, 1 cup sour cream, 1/2 cup vegetable oil, 1/2 cup whole milk, and 1 1/2 cups crushed Oreos. Beat on medium speed for 2 minutes until smooth and thick. Scrape sides as needed for even mixing.

4-Fourth Step: For the optional cream filling, beat 8 oz softened cream cheese, 1/2 cup powdered sugar, 1 tsp vanilla extract, and a handful of crushed Oreos until creamy. Pour half the batter into the prepared pan. Dollop the filling over the batter, avoiding the edges. Top with remaining batter, smoothing gently.

5-Fifth Step: Bake for 45-55 minutes. Test doneness with a toothpick inserted in the center; it should come out clean or with moist crumbs. Avoid overbaking to keep it moist.

6-Sixth Step: Cool in the pan for 15 minutes. Run a thin knife around the edges and center tube. Place a cooling rack over the top, invert, and lift off the pan. Cool completely.

7-Final Step: Whisk 1 cup powdered sugar with 2 tbsp milk until smooth for the glaze. Drizzle over the cooled bundt cake recipe. Sprinkle reserved 1/2 cup crushed Oreos on top. Slice and serve. For vegan adaptations, use plant milk in glaze; gluten-free works with swaps from earlier.