Spray a non-stick donut pan and preheat the oven to 350 F/180 C.
In a large mixing bowl, mix the fruity pebbles and buttermilk together. Set aside while you measure the rest of the ingredients.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In the same mixing bowl with the cereal milk, whisk in the melted butter, sugar, egg, sour cream, oil, and vanilla.
Whisk the dry ingredients into the wet until just combined.
Fill a piping bag with the batter.
Pipe the batter into the six donut molds so they are ¾ full.
Bake for 9-10 minutes or until the tops spring back when touched.
Let the tray cool on a wire cooling rack. (After 10 minutes, you can carefully remove the donuts from the pan, wash it, and fill it with the rest of the batter for 4 more donuts.) Whisk together the powdered sugar, milk, food coloring, lemon extract, and vanilla extract until smooth. The glaze should be thick! Dunk one donut into the glaze and determine if you need more powdered sugar or milk. The glaze should sit on top of it and just barely drip down the sides. If you can see the donut through the glaze you can add more sugar. Once glaze, immediately sprinkle with fruity pebbles. Enjoy!