How to build it
● Spoon some of the beef mixture into a shallow ovenproof baking dish, so that it completely covers the bottom. ● Place the discs of the raw sweet potato on top of the beef mixture, ensuring that it completely covers the beef mixture. ● Repeat the process so that you have two layers of beef mixture and two of sliced sweet potato, then finish with a layer of beef on top. ● Cover the top layer of beef with yogurt, and then scatter the grated cheese over the top. ● Place the lasagne in a preheated oven at 180°C/ gas 4 for 25-30 minutes.