Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, cream together softened unsalted butter, granulated sugar, and brown sugar for 2-3 minutes until light and fluffy.

Beat in the eggs one at a time, followed by the vanilla extract, scraping down the sides of the bowl after each addition.

Gradually add all-purpose flour, mixing on low speed until just combined, about 30 seconds.

Gently fold in the crushed Fruity Pebbles until evenly distributed.

Scoop generous mounds of dough onto the baking sheets, spacing them about 2 inches apart.

Bake for 10-12 minutes, or until the edges are golden and the centers remain soft. Allow to cool for a few minutes.

Spread frosting on each cooled cookie and add sprinkles or additional Fruity Pebbles on top.