Preheat oven to 350°F and grease donut pan
Combine 1 cup of Fruity Pebbles and buttermilk in large mixing bowl, set aside
Mix dry ingredients (flour, baking powder, baking soda)
Add lightly whisked egg, oil, vanilla, greek yogurt, and melted butter to bowl with cereal and buttermilk, stir until mixed
Slowly add flour mixture to buttermilk mixture until well combined
Fill prepared donut pan about ¾ full
Bake for 10 minutes or until bouncy on top
Let cool for 15-20 minutes in the pan
Mix together glaze ingredients, excluding cereal, until combined
Dip donuts in glaze and place on parchment paper
Sprinkle crushed cereal over glazed donuts in a diagonal direction
Serve and enjoy!