Directions:

Preheat your oven to 350°F (or 375°F if specified in your recipe). Prepare a baking sheet by lining it with parchment paper or greasing it lightly.

In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar for 2-3 minutes until the mixture is well combined and fluffy.

Add the eggs one at a time, mixing in between each addition, and incorporate a splash of vanilla extract if desired for added flavor.

In a separate bowl, whisk together the all-purpose flour, baking powder, and baking soda. Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Gently fold in the Rice Krispie cereal and semi-sweet chocolate chips, taking care not to crush the cereal too much. If using, add shredded coconut and marshmallows at this stage.

Using a cookie scoop or a tablespoon, drop 2-tablespoon sized scoops of dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake the cookies in the preheated oven for 8-10 minutes or until the edges are lightly golden brown. Keep an eye on them to avoid over-baking.

Once baked, allow the cookies to cool on the baking sheet for 2-3 minutes before transferring them to a wire rack to cool completely.

For best results, remember to measure your ingredients accurately, especially the flour, as too much can lead to dry cookies. If you want a gooey center, consider adding a few extra marshmallows in the dough or placing one on top before baking.

Additionally, feel free to experiment with other mix-ins like butterscotch chips or peanut butter chips for a customized cookie experience!