1 Heat a pan and toast the tortillas, one by one, without adding oil.
2 Add a glug of oil to the same pan and brown the pork mince, breaking it up with a spatula once the pork has started to colour.
3 Add the seasoning and mushrooms and continue cooking for a few more minutes until the mushrooms soften. Stir in the tomato-and-onion relish and cook for 5 minutes or until the sauce is reduced. You want the meat to be juicy but not too saucy. Remove from heat and allow to cool slightly.
4 Preheat the oven. Lay the first tortilla on a baking tray lined with baking paper and spread two tablespoons of white sauce. Spread 1/5 of the pork mince mixture over this and sprinkle with cheese. Top with another tortilla and continue layering the filling ingredients. Ensure you finish with white sauce and a generous sprinkling of cheese.
5 Bake the stack for 20 minutes until heated, then grill for 5 minutes until golden brown. Serve in wedges with your favourite toppings; it’s delicious warm or at room temperature.
To make your white sauce, melt 45ml butter over moderate heat in a small saucepan. Add 45ml flour and beat with a balloon whisk until smooth (this mixture is called a ‘roux’). Cook for a minute until frothy. Remove from the heat and gradually whisk in 250ml hot stock and 250ml hot milk until smooth. Put back on the heat, add a bay leaf (optional) and cook over moderate heat until it thickens; stir gently throughout to prevent it from catching. Remove from the heat, discard the bay leaf and season with salt, pepper and nutmeg to taste.