1-First Step: Gather and Prep Line a 9×13-inch pan with parchment or grease lightly. Chop 20 chocolate sandwich cookies roughly; set aside. Measure 6 cups puffed rice cereal. Divide marshmallows: 12 ounces for melting, 8 ounces whole. Have 1/2 cup salted butter ready. This mise en place keeps things smooth, especially for beginners or busy parents.

2-Second Step: Melt the Butter In a large saucepan, melt 1/2 cup salted butter over low heat. Stir occasionally to avoid browning. Low heat prevents burning, key for smooth texture in Oreo Rice Krispie bars. Takes about 2 minutes.

3-Third Step: Melt Marshmallows Stir in 12 ounces mini marshmallows. Cook over low heat, stirring frequently, just until melted. Remove from heat right away. Tip: Cook only until melted to avoid overcooking, as noted in recipe tips. This keeps the mixture gooey, not tough.

4-Fourth Step: Mix in Cereal and Remaining Marshmallows Add 6 cups puffed rice cereal and 8 ounces remaining marshmallows. Stir until combined and marshmallows soften slightly. The whole ones add chewy pockets. Works well for vegan swaps too, just use plant-based versions.

5-Fifth Step: Fold in Cookies Fold in roughly chopped 20 chocolate sandwich cookies until evenly mixed. Gentle folds preserve cookie crunch. For gluten-free Oreo Rice Krispie treats alternative, use gf cookies here.

6-Sixth Step: Press into Pan Pour mixture into prepared 9×13-inch pan. Gently press into even layer. Spray hands with cooking spray or use a rubber spatula to prevent sticking. Press lightly for soft treats.

7-Final Step: Cool and Serve Let cool to room temperature, about 30-60 minutes. Cut into squares. Press extra broken cookies on top for more flavor. Serve as no-bake Oreo dessert squares for parties.