4chicken breasts (about 700g/1.5lbs), sliced in half to make 8 thin, wide breasts (you can slice each breast into 3 slices, to make 12 slices altogether if you're serving 6 people)
500g(2 ¼ cups) passata* (tomato puree for US)
1tspdried Italian mixed herbs
100g(1 cup) Cheddar cheesegrated
White Sauce:
4tbsp(60g) unsalted butter
4tbspplain (all-purpose) flour
400ml(1 ⅔ cups) milk (full or half-fat)
⅛tspsalt
⅛tsppepper
pinchground nutmeg
25g(¼ cup) Cheddar cheesegrated
Instructions
Preheat the oven to 200C/400F (fan).
First make the white sauce. In a medium sized saucepan, add the butter and melt over a medium heat.
4 tbsp (60g) unsalted butter
Once melted and bubbling slightly, add in the flour and stir it into the butter using a whisk (this will form a thick paste called a roux).
4 tbsp plain (all-purpose) flour
Keep gently stirring the roux over the heat for one minute to cook the flour. Add in a good splash of the milk, turn up the heat and stir with the whisk to incorporate.
400 ml (1 ⅔ cups) milk
Keep adding in the milk a good splash at a time, and whisking until all the milk is used up (this normally takes me about 3 or 4 minutes and I add the milk in about 5 splashes). Don't worry if you get a few lumps, keep stirring with the whisk and they will disappear as the sauce thickens.
Keep stirring the sauce with the whisk over the heat until the sauce thickens. Once thickened, add in the salt, pepper, nutmeg, and cheddar. Stir together and then turn off the heat.
⅛ tsp pepper, pinch ground nutmeg, 25 g (¼ cup) Cheddar cheese, ⅛ tsp salt
Now take a large baking dish or casserole pan.
Add the chopped onion, mushrooms, garlic, red pepper, olive oil, crumbled chicken stock cube, salt, and pepper to the pan and stir together. Note: the pan doesn't need to be on the heat for this. The ingredients go into the oven raw, where they'll cook down together.
1 onion, 6 medium mushrooms, 2 cloves garlic, 1 red bell pepper, 2 tsp olive oil, 1 chicken stock cube, ¼ tsp salt, ¼ tsp pepper
Add half of the slices of chicken in one layer on top of the onion mixture.
4 chicken breasts
Drizzle over half the passata, sprinkle on half the dried herbs and spoon on half the white sauce.
500 g (2 ¼ cups) passata*, 1 tsp dried Italian mixed herbs
Layer the remaining chicken slices on top, followed by the remaining passata, then the remaining dried herbs and the remaining white sauce.
Sprinkle the grated cheddar on top.
100 g (1 cup) Cheddar cheese
Place in the oven for 40 minutes, until the chicken is cooked through, the cheese is browned and the sauce is bubbling.
Notes
*PassataI'm using passata in this recipe for a smooth sauce. If you're in the USA, passata is the same as tomato puree. It's a medium-thick sauce (about the consistency of double/heavy cream) made of 100% tomatoes. If you can't get hold of it you can replace with the same amount of finely chopped or crushed tinned/canned tomatoes - you will just need to simmer the sauce for a few minutes longer.Can I make it ahead?Yes, you can make this dish up to a day ahead. Make the dish, but don't put in the oven. Cover and refrigerate for up to a day. When you're ready to cook it, take it out of the fridge about an hour before you plan to cook it - to take off the chill. Then cook for 40-50 minutes at 200C/400F - until the chicken is piping hot and fully cooked.Can I freeze it?Yes, but it's best to cook the dish first, then cool, cover and freeze.Defrost in the refrigerator overnight (ensure it's fully defrosted), then take out of the fridge about an hour before you plan to reheat it - to take off the chill. Then place in the oven, covered with foil and cook for 40-50 minutes (take the foil off for the last 10 minutes) at 200C/400F - until the chicken is piping hot.How to scale down this recipeYou can halve the recipe to serve 2-3 people by halving all of the ingredients and using a smaller casserole dish. The cooking time will stay the same as the original recipe (40 minutes).Nutritional information is per serving (serves 6)