- Peel and chop the potatoes. Boil in water until fully cooked through. 
- Drain and mash. 
- Add the milk and butter. Season with salt and pepper. 
- Heat up the olive oil in a pan over medium heat. 
- Add the chopped onion and garlic, and cook until translucent. 
- Transfer the mixture to the mashed potatoes. Add the yogurt/sour cream, flour, green onion, and cheese. Mix to combine. 
- Brush the liners with oil. Fill half of them with the mashed potato mixture. 
- Put 1 Brussel sprout in the middle, then top up with more mash. 
- Bake at 180 degrees Celsius for 20-25 minutes. 
- minutes before they’re done, add a bit more shredded cheese on top.