MASH: Cut the avocados in half, remove and discard the pits and scoop the avocado into a bowl. Use a fork to mash them as roughly or smoothly as you like, then add the green onions, lime juice and salt, folding in to make a nicely combined guacamole.
BROWN: Add the ground beef to a skillet over medium heat. Cook, breaking up with a spatula or the back of a spoon, until the beef is in bite size pieces, the fat has rendered and the meat is just beginning to brown. (If your ground beef isn’t particularly lean, you may want to drain off any excess fat at this point).
SEASON: Pour the broth or water into the skillet, along with the oregano, cilantro, garlic, ginger, onion powder and salt. Stir to combine. Simmer until the liquid has evaporated and the meat is evenly coated in the seasoning, about 3 or 4 minutes. Turn off & remove from the heat, then cover the pan with a lid to keep warm.
RICE: While the beef is browning, peel the white sweet potato. Using the medium grating attachment of your food processor, coarsely grate the sweet potato. Add the grated sweet potato to a bowl and swap the grating attachment for the S blade. Working in two or three batches so as not to overcrowd the bowl, add the grated sweet potato back to the bowl and pulse just a few times until you have rice-sized pieces. Repeat until all the sweet potato is riced.
COOK: Heat a skillet over medium heat. Add the riced sweet potato to the skillet. When you hear the sweet potato starting to sizzle, add the broth, garlic and salt, stirring to combine. Cover the skillet and cook until the liquid has almost completely absorbed, about 3 minutes. Stir to prevent the rice sticking, then cover and cook until just tender, about another 2 or 3 minutes. Turn off the heat and remove the skillet from the stove top, Stir and fluff the rice, then let it release steam while it cools a little and finishes absorbing the broth. Add the minced cilantro and stir it through.
BLEND: Add all of the yogurt sauce ingredients to either the bowl of a mini food processor, or the blending container that fits your immersion blender. Blend until the yogurt sauce is smooth.
ASSEMBLE: Divide the chopped romaine, cabbage, red onion and radishes between bowls. Pile in the sweet potato rice, seasoned ground beef and guacamole. Drizzle with the yogurt sauce and add the plantain chips on the side.