Peel sweet potatoes, cut into smaller pieces, and steam for 15 minutes or until they are tender. Mash and let them cool down.
Once cooled, add protein powder and glutinous rice. Add green onion, salt and pepper. Mix well with hands.
Use a tablespoon to scoop sweet potato mixture, flatten with thumbs, add a pinch of cheese in the center, and fold all sides up and seal the sweet potatoes. Roll them into ball shape.
Preheat a non-stick pan and drizzle with oil; turn to medium heat. Place sweet potato balls onto the pan; slightly flatten them with the back of the spoon. Cook for about 2 minutes or until crusted.
Flip and again flatten. Cook for another 2 minutes. You may flip them a couple of times as needed. Serve immediately.