Martha Collison’s spiced beef & aubergine lasagne

1. Heat the olive oil over a medium heat in a large saucepan or casserole dish that has a lid (to use later). Once the oil is hot, add the onions and garlic fry for 10-15 minutes, stirring regularly, until soft. You are looking just to soften the onions, rather than colour them.

2. When the onions are soft, turn the heat up slightly and add the beef mince. Use your wooden spoon to break up any large chunks and fry for 5-10 minutes, until browned all over and no pink bits can be seen. Add the spices and aubergine cubes. Turn the heat down to low and stir in the tomato purée and chopped tomatoes. Measure the beef stock (or add hot water to a stock cube) in the tomato can (the liquid will fill the can by ¾) and add to the mixture, washing any remaining tomato left in the tin into the ragù. Cover and simmer for 30 minutes. Once cooked, season to taste with salt, then allow to cool slightly before using or allow to cool completely, cover and refrigerate for up to 3 days.

3. While the ragù is simmering, make the cheese sauce. Melt the butter in a medium saucepan, then whisk in the flour. Cook for 2 minutes until it smells toasty, then add the tahini. It won’t turn smooth like an ordinary roux and may look clumpy, but persevere. Add a large splash of the milk. Whisk vigorously until smooth, then gradually add the rest of the milk, stirring all the time.

4. Once all the milk has been incorporated, heat the mixture gently, stirring, until thickened. Stir in half the Parmigiano Reggiano and season well with black pepper before removing from the heat. Stir in the yogurt. Use straightaway or allow to cool completely, cover and chill for up to 3 days.

5. When you are ready to bake, preheat the oven to 200°C, gas mark 6 and get out a large baking dish. Spread ⅓ of the ragù into the base of the dish, then top with a layer of lasagne sheets. Spread ¼ of the cheese sauce over the pasta layer, then repeat the ragù, pasta and cheese sauce twice more. Pour the remaining cheese sauce over the top, making sure the pasta is completely covered, then sprinkle with the remaining Parmigiano Reggiano and oregano.

6. Bake for 35-40 minutes until the top is bubbling and golden. Use a sharp knife to test the lasagne in the middle. It should slide through the pasta easily. Serve immediately with a simple green side salad, if liked.