Make the Donuts: In a small saucepan, heat the milk to 100-110F. Add the yeast and 1/2 tsp of the sugar and stir. Let sit 5-10 minutes or until frothy. Transfer the milk mixture to the bowl of an electric mixer fitted with the paddle attachment. Add the rest of the sugar, salt, eggs, and butter and stir to combine. Add half the flour and stir until incorporated, then add the rest of the flour and continue mixing until a dough ball forms, pulling away from the sides of the bowl. If dough is too sticky to handle, add more flour 1 tbsp at a time until a nice dough consistency is formed.

Turn the dough out onto a floured surface and knead until just smooth. Transfer to an oiled bowl, cover with cling wrap, and rest for 1 hour at room temperature. (If your kitchen is very cold, heat the oven to 200, then turn OFF and put the dough inside. Keep the door ajar halfway.)

While the dough rests, make the topping. Pulse the fruity pebbles and sugar in a food processor until finely crushed and well combined. Transfer the mixture to a large bowl and stir in the lemon zest with a fork. (Mix vigorously, the zest likes to stick to itself!)

On a floured surface, roll out the dough to about a half inch thickness and cut out doughnuts and holes. Place the cut donuts on 2 large parchment-lined baking sheets with about 1 inch of space between each. Knead together the scraps until smooth and rest 5 minutes before rolling and cutting again. (Re-roll only once to avoid tough donuts!) Cover each baking sheet with a clean kitchen towel, and let rest in a warm place until puffed up, about 45 minutes. (Again, if your kitchen is not warm, heat the oven to 200, then turn OFF and add doughnuts, keeping the door ajar.)

In a large dutch oven or pot, heat the oil to 370F. (Do not fill your dutch oven or pot more than halfway full with oil.) Use your heat-proof slotted spoon or spider to carefully lower the donuts into the oil and to flip them. Fry the donuts 2 at a time for 1-2 minutes per side, then transfer to a wire rack (fitted over a baking sheet to catch any oil) to cool.

Make the glaze: In a medium saucepan, combine the butter, milk, and vanilla, and heat until milk begins to steam. Whisk in the confectioners sugar a little at a time until well combined. Remove from the heat. Dip each donut into the glaze and place back on the rack to cool. While the glaze is wet, sprinkle the fruity pebbles mixture generously over the donuts and enjoy!