1. Preheat your oven to 350°F and line two baking sheets with parchment paper.
2. In a large bowl, cream together the butter, granulated sugar, and brown sugar until light and fluffy, about 3-4 minutes.
3. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
4. In another bowl, whisk together the flour, baking soda, and salt. Gradually add this to the wet ingredients, mixing until just combined.
5. Gently fold in the Fruity Pebbles cereal.
6. Scoop a tablespoon of dough and flatten it slightly in your hand. Place a few mini marshmallows in the center and wrap the dough around them, rolling it into a ball to seal the marshmallows inside.
7. Place the cookie dough balls onto the prepared baking sheets, leaving about 2 inches between each one.
8. Bake for 10-12 minutes or until the edges are golden and the centers are set.
9. Allow the cookies to cool on the baking sheets for about 5 minutes before transferring them to a wire rack to cool completely.

Don’t rush through the cooling process; letting them rest ensures the marshmallow centers set perfectly, creating that delightful gooey surprise when you bite into them.