METHOD

1. Preheat oven to 200°C (400°F). Heat the oil in a large non-stick frying pan over high heat. Add the mushrooms, salt and pepper and cook for 7 minutes. Add the thyme, transfer to a bowl and set aside. 
   
2. Wipe the pan clean and melt the butter over medium heat. Add the flour and whisk for 1 minute. Gradually add the milk, whisking to combine. Increase heat to high and bring to the boil.  Whisk constantly for 1 minute or until thickened. Remove from the heat and whisk in 1 cup of the pecorino. 
   
3. Cook the ravioli following packet instructions and drain. Spread ½ cup of the sauce on the base of a 3-litre-capacity ovenproof dish and top with one-third of the ravioli. Top with 1 cup of the sauce, 2 tablespoons of relish and one-third of the mushrooms. Repeat to make 2 more layers. 
   
4. Top with mozzarella and remaining pecorino. Cook in the oven for 20 minutes or until golden. Serves 4–6.