Combine onion, garlic and bacon in a bowl.
Layer sweet potato slices in bottom of bowl, place layer of potato on top, layer of mushrooms, sprinkle onion, garlic and bacon over mushrooms then chicken fillets. Repeat until almost to top of insert.
Sprinkle salt and pepper over the top, pour cream and milk over.
Cook for 5-6 hrs on high (Crockpot 3.5L sc).
Approx 30 minutes prior to serving top with grated cheese, cover with tea towel and cook until melted.