In the bottom of the slow cooker, add olive oil, followed by cubed chicken, mushrooms, garlic, seasoning, onions and lemon juice.
Cook for 4 hours on high or 6 hours on low.
Combine the flour and heavy cream to make a roux.
Add the roux, cheese and butter to the slow cooker then stir to combine. Leave to cook for 10 minutes to allow the cheese to melt.
Serve over pasta with slices of mozzarella.