In a large pot over medium heat, add the horchata and bring to a boil. Once boiling, add the ramen and allow to cook until fully softened, about 8-10 minutes.
Drain the ramen from the horchata and transfer to a large deep rectangular tray. Press the ramen into one even layer making sure it's tightly packed and sticking together.
Allow the ramen to set in the fridge for 3 hours - overnight
Once set, cut the ramen into the shape of a donut using a large glass and a small bowl. Carefully lift each donut out of the tray and transfer to a large cookie sheet while heating the oil.
Heat the oil in a large deep pan for 4-6 minutes. Test the oil with a tiny piece of ramen. If the oil bubbles and the ramen browns, gently drop on the first donut using a spider or a large slotted spoon.
Allow the ramen to fry on the first side for 2-3 minutes or until a nice golden brown. Using the spider or slotted spoons, gently and carefully flip over the donut and allow to fry for another 2 minutes on the second side.
Remove the donut from the oil and allow them to drain on a plate line with paper towels. Repeat this process until all of the donuts have been fried.
To make the matcha frosting, simply mix the matcha powder into the vanilla frosting and stir until even in color. Transfer all 3 frostings to a large shallow bowl in preparation for dipping the donuts
Once drained of the oil and cool enough to touch, dunk the donuts into the frosting, generously coating each donut. Immediately garnish with sprinkles then allow to set for 5-10 minutes before serving.