Heat 1 tbsp garlic oil in a large saucepan. Add all the vegetables and cook for around 10 minutes, until browned and starting to soften, stirring frequently.
Meanwhile, rub the harissa paste all over the lamb steaks and set aside.⠀
Add the spices to the vegetables, stir well, and cook for 1-2 minutes. Add the tinned tomatoes and stir well to combine. Leave to cook for approx 20 minutes, stirring occasionally.⠀
Fry the lamb steaks in oil over a high heat for 1-2 minutes each side. Turn down the heat and cook for a further 3-4 minutes on each side (depending on how well-done you like it). Turn off the heat and allow to rest until the vegetables are cooked.⠀