Step 1: Prepare the Chocolate-Oreo Base

1. In a food processor or zip-top bag, crush 18 Oreo cookies into fine crumbs (1 ½ cups total). Reserve ½ cup for topping.

2. In a large bowl, whisk together 1 ½ cups all-purpose flour, ¾ cup granulated sugar, ¼ cup unsweetened cocoa powder, 1 cup crushed Oreos, 1 tsp baking powder, and ¼ tsp salt until well combined.

3. In a separate bowl, mix ½ cup melted unsalted butter, ½ cup milk, and 1 tsp vanilla extract until smooth. Add to the dry ingredients and stir until a thick, cake-like batter forms.

   • Tip: Crush Oreos finely for even flavor distribution. Mix batter gently with a spatula to avoid overmixing, ensuring a tender texture. Ensure dry ingredients are lump-free before adding wet ingredients.

Step 2: Prepare the Creamy Swirl

1. In a medium bowl, beat 4 oz softened cream cheese until smooth, about 1 minute with an electric hand mixer.

2. Add 1 cup thawed whipped topping and mix until fully blended and creamy.

3. Set aside or refrigerate if not using immediately.

   • Tip: Soften cream cheese at room temperature for easier mixing. Fold whipped topping gently to maintain airiness. Store in the fridge if prepping ahead to keep fresh.

Step 3: Layer in the Slow Cooker

1. Lightly grease a 4-6 quart slow cooker insert with cooking spray or a thin layer of butter to prevent sticking.

2. Spread half the chocolate-Oreo batter evenly across the bottom of the slow cooker with a spatula.

3. Spoon dollops of the creamy swirl over the batter, covering about half the surface, creating a marbled effect. Do not stir; the layers will meld during cooking.

4. Spread the remaining chocolate-Oreo batter over the creamy swirl, smoothing gently to cover.

   • Tip: Use a slow cooker liner for easy cleanup. Drop creamy swirl in small portions for a marbled effect. Spread top batter gently to maintain layers.

Step 4: Slow Cook

1. Cover and cook on low for 2-3 hours, until the base is set and a toothpick inserted in the center comes out with moist crumbs (not wet batter).

2. Check doneness at the 2-hour mark; if the top looks too wet, remove the lid for the last 30 minutes to evaporate excess moisture.

   • Tip: Place a paper towel under the lid to catch condensation and prevent a soggy surface. Avoid lifting the lid too often to maintain heat. Cooking times vary by slow cooker model.

Step 5: Prepare the Topping

1. Warm ¾ cup hot fudge sauce in a microwave-safe bowl in 15-second intervals, stirring until pourable (about 30-45 seconds total). Alternatively, heat on the stovetop over low heat.

2. Ensure ½ cup crushed Oreos and 1 cup thawed whipped topping are ready for assembly.

   • Tip: Warm hot fudge just before serving for easy drizzling. Crush Oreos coarsely for texture. Keep whipped topping chilled until assembly.

Step 6: Assemble and Serve

1. Turn off the slow cooker and let the dessert cool for 5-10 minutes to set slightly, making it easier to scoop.

2. Scoop the warm Oreo-hot fudge casserole into 8-10 bowls or dessert cups (about ½ cup per serving), ensuring each portion has a mix of chocolatey base, creamy swirl, and Oreo crumbs.

3. Top each serving with a dollop of whipped topping (about 2 tbsp). Drizzle with 1-2 tsp warm hot fudge and sprinkle with 1 tbsp crushed Oreos.

4. Serve warm for a gooey, chocolatey experience. Pair with coffee, hot chocolate, or a dessert liqueur (like Baileys) for an indulgent vibe.

   • Tip: Swirl whipped topping and drizzle hot fudge artfully for a polished look. Serve in wide bowls to showcase the gooey layers and crunchy toppings. Offer extra Oreo crumbs or hot fudge on the side for customization.