Pre-heat your oven to 400 degrees. Line a baking sheet with foil or parchment and spray it lightly with cooking spray. (You really don’t want your sweet potatoes to stick.) Scrub your sweet potatoes and pat them dry. Pierce each potato 2 or three times with a fork, and place them on the prepared baking sheet. Roast for 50 minutes to 1 hour until the potatoes are very tender. (Heads up, if you’re using bigger potatoes, they may take up to 1 hour and 15 minutes.)
While the potatoes roast, get going on your mushroom filling. Start by prepping the mushrooms, wash the caps well, pat them dry, and remove the stems. Using a spoon, remove the dark gills from their undersides. Roughly chop the cleaned caps.
Place the chopped mushrooms and onions in a food processor. Pulse a few times until finely chopped. (You can also chop your mushrooms/onions finely by hand if you don’t have a food processor.)
Heat the olive oil in a medium non-stick skillet over medium heat. Add the spices and salt to the pan and cook for 2 minutes until they're toasted and fragrant.
Add the mushrooms and onions to the pan along with the apple cider vinegar. (It will seem like a lot of ‘shrooms, but they’re going to cook down!) Cook for 10-12 minutes until the mushrooms have released all their liquid. Then turn up the heat to high and cook for a minute or two to get a little crispy/char on some of the mushrooms. (This mix will look a little like ground beef.) Transfer the mushrooms to a bowl and cover with foil.)
Combine all the ingredients for the pico de gallo in a mixing bowl. Season with salt and fresh ground pepper to taste. Cover and refrigerate until ready to use.
Assembly time! Cut a slit in the top of each sweet potato and roughly mash the insides with a fork. Season with salt and pepper. Spoon a quarter of the mushroom filling into each of the sweet potatoes. Pre-heat your broiler on high. Top each potato with ¼ cup cheese. Place the sweet potatoes under the broiler until the cheese is melted and bubbling, usually about 2 minutes.
Transfer the potatoes to a serving dish (or individual plate/bowls) and top with plenty of pico de gallo. Serve with guacamole and lime wedges if you're feeling festive.