Preheat the oven to 180°C.
Place the fillets into a medium pot of water, bring to the boil then turn heat down to a gentle simmer and pack the meat for +- 12 minutes. Remove, cool and thinly slice on the diagonal.
Place the milk, onion, celery and bay leaves into a medium pot and heat up gently. The minute steam comes out of the pot, remove from the heat, cover and allow the milk to infuse.
Steam the butternut, cauliflower and broccoli and courgettes separately until al dente. Must be cooked through but firm to the bite and the colour needs to stay vibrant. Lightly season the vegetables.
Strain the milk and discard the onions.
In a medium sauce pan, heat the oil and butter until simmering, add the mushrooms and season with a little salt. Fry until softened and slightly browned. Remove from the heat and stir in flour until well combined.
Place back onto moderate heat and slowly add the infused milk, stirring all the while to prevent lumps. Cook and stir until thickened and the sauce coats the back of the spoon. Remove from the heat.
Add the cheese and mix until well combined. Season sauce with a little nutmeg, salt and pepper.
In a large baking dish, arrange the sliced chicken and steamed veggies in layers. Pour over the cheesy mushrooms sauce making sure all the ingredients are covered.
Mix the cheese, crumbs and rosemary together and sprinkle on top.
Pop into the oven and bake for +- 40 minutes or until golden and bubbling up on the sides.
Serve with a crisp green salad.Recipe reprinted with permission of BitsofCarey. To see more recipes, click here.