1-First Step: Start by preparing your mise en place. Ensure your butter is softened to room temperature so it creams easily with the sugars. Preheat your oven to 350°F and line two large baking sheets with parchment paper. This prevents sticking and makes cleanup effortless.

2-Second Step: In a large bowl, cream together 1 cup of softened butter, 1 cup of light brown sugar, and 1/2 cup of granulated sugar. Beat on high speed for about 3 minutes. You want the mixture to be pale and fluffy, which incorporates air into the dough for a lighter texture. If you are watching your sugar intake, this is the stage where you might mix in your sugar substitutes.

3-Third Step: Add the 2 large eggs and 1 teaspoon of vanilla extract to the butter mixture. Beat again until the eggs are fully incorporated and the mixture looks glossy. Scrape down the sides of the bowl to ensure everything is evenly mixed. This step is crucial for emulsifying the ingredients.

4-Fourth Step: In a separate medium bowl, whisk together the dry ingredients: 2 1/2 cups of all-purpose flour, 2/3 cup of unsweetened cocoa powder, 1 teaspoon of baking soda, and 1/2 teaspoon of salt. Whisking these together ensures the leavening agents are evenly distributed throughout the flour, preventing pockets of bitter baking soda in your finished cookies.

5-Fifth Step: Gradually add the dry flour mixture to the wet ingredients. Mix on low speed just until the flour streaks disappear. Be careful not to overmix, as this can develop the gluten in the flour and make the cookies tough rather than chewy. The dough will be thick and dark.

6-Sixth Step: Cover the bowl and place the dough in the refrigerator to chill for at least 30 minutes. This step is vital because chilled dough produces thicker cookies with a richer flavor. It prevents the cookies from spreading too flat in the oven, ensuring they remain soft and fudgy in the center.

7-Seventh Step: Once chilled, scoop the dough using a 1/4 cup measuring scoop to form large balls. Place them on the prepared baking sheets, leaving about 2 inches of space between each ball to allow for spreading. For the authentic Crumbl experience, do not flatten the balls; let them spread naturally.

8-Eighth Step: Bake the cookies in the preheated oven at 350°F for 10 to 12 minutes. You will know they are done when the edges look set and matte, but the centers still look slightly soft and underbaked. Remove them from the oven and let them cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. They will finish cooking on the hot pan.

9-Ninth Step: While the cookies are cooling, prepare the frosting. In a microwave-safe bowl, heat 3/4 cup of heavy whipping cream until it is simmering, which should take about 1 minute. Pour the hot cream over 1 cup of semi-sweet chocolate chips. Let it sit for 2 minutes to soften the chocolate without stirring.

10-Tenth Step: After 2 minutes, stir the mixture vigorously until the chocolate is completely melted and the ganache is smooth and glossy. Whisk in 1/2 cup of powdered sugar and 1/4 cup of softened butter until the frosting is creamy and spreadable. If the consistency is too thick, add a teaspoon of cream; if it is too thin, let it chill in the fridge for 5 minutes.

11-Final Step: Once the cookies are completely cool, spread about 2 to 3 tablespoons of the ganache onto each cookie. Use an offset spatula to create a smooth, even layer. Immediately sprinkle the mini M&Ms or colorful candy pieces on top before the frosting sets. Let the frosting firm up for about 15 minutes before serving.