Preheat the oven to 200˚C.
In a saucepan, over medium heat, melt the butter or oil and add the bacon and leek. Cook for 2 minutes until just translucent. Remove the leeks in a dish until required.
Add the garlic cloves and chicken to the pan and cook for a further minute or two to warm up the chicken pieces. Season with salt and pepper.
Then, sprinkle the chicken pieces with some flour and stir to coat the pieces with the flour. Cook for a minute then slowly mix in the milk while simmering until a light and coating consistency is achieved. Remove from the heat and pour the mixture in a ceramic dish with the leeks sitting on top. Sprinkle with the cheddar, parmesan and goat cheese and place in the oven. Bake for 10-15 minutes until bubbling and coloured.
Serve immediately and enjoy while hot!