Add all remaining ingredients to cooker -crumbling the stock cubes
Mix everything together - covering chicken breasts with the mixture
Cook on low for approximately 4.5 hours on low - check after 3.5 hours as breasts dry out easily.
(My slow cooker is 9.5L & cooks hotter then usual so times will vary)
Cooking as a pie instructions (optional)
Slice mushrooms & bacon.
Add all ingredients to low cooker - leaving chicken breasts whole.
Cover breasts with mixture & cook on low for 4.5 hours.
I refrigerated chicken breasts & mushroom sauce mixture over night.
Preheat oven to 180°c
Line a tart tray with puff pastry & cook the base until golden - put something on top to weight it down and pierce with a fork.
Using gravy granules thicken the mushroom sauce & chicken mixture.
Add mixture to pre-cooked pastry base.
Slice 2 sheets of puff pastry into 2cm slices and "criss-cross" along the pie, tucking into the sides.
Brush with milk and cook for approximately 30 mins until the top is golden & the filling is piping hot (to reheat chicken thoroughly.)
Notes
Note: I used this mixture the previous night served over mash with veggies so made 1 pie with left overs. This amount could probably make 3 family sized pies. Mixture could be frozen for dump bags etc.