PREHEAT THE OVEN: Set the oven to 350°F (175°C) and line two baking sheets with parchment paper to prevent sticking and promote even baking.
CREAM THE BUTTER AND SUGARS: In a large mixing bowl, use an electric mixer on medium speed to cream together the softened butter, brown sugar, and granulated sugar until the mixture is light in color and fluffy in texture, about 2 to 3 minutes.
ADD EGGS AND VANILLA: Add the eggs and vanilla extract to the creamed butter mixture. Beat until the eggs are fully incorporated and the mixture looks smooth.
COMBINE DRY INGREDIENTS: In a separate bowl, whisk together the flour, baking soda, baking powder, and salt to evenly distribute the leavening agents and salt throughout the flour.
ADD DRY INGREDIENTS TO WET: Gradually add the dry mixture to the wet ingredients, mixing on low speed or by hand just until no dry streaks remain. Avoid overmixing to maintain a tender texture.
FOLD IN CEREAL AND CHOCOLATE: Gently fold in the Rice Krispies and chocolate chips using a spatula or wooden spoon, mixing only until evenly dispersed. The dough will be chunky and textured.
SCOOP DOUGH: Use a medium cookie scoop (about 2 tablespoons) to portion the dough and place the mounds at least 2 inches apart on the prepared baking sheets to allow for spreading.
BAKE COOKIES: Bake for 10 to 12 minutes, or until the edges are lightly golden and the centers look just set. Do not overbake, as the cookies will continue to firm up while cooling.
COOL BEFORE SERVING: Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely for best texture and flavor.