Method
1. Warm a large frying pan (or casserole dish, if you’re braising the beef on the hob) for 2 mins, then add 1 tbsp oil and add the beef strips. Fry for 8-10 mins till the beef is browned.
2. While the beef is cooking, peel and finely chop the onion. Peel and thinly slice the garlic cloves. Peel and grate the ginger. Halve the chilli (the chilli is optional, so if you prefer a milder curry, leave the chilli out) and scoop out the seeds and white pith (or leave them in for more heat), then finely chop it. From this point, follow the method for cooking the curry in the slow cooker or on the hob.
3. In the Slow Cooker: Tip the beef into a 3½ ltr slow cooker. Add in the onion, garlic, ginger and chilli (if you’re using it). Dice the tomatoes and add them to the slow cooker. Sprinkle in the Bombay spice mix and add a good pinch of salt and pepper. Gently stir to mix.
4. Peel and chop the potatoes into 3-4cm chunks. Add the potatoes. Pour in 400ml boiling water. Stir well then pop on the lid. Set the slow cooker to medium and cook for 8 hrs. For a faster curry, set the slow cooker to high and cook for 5-6 hrs, or set to low and cook for 8-10 hrs.
5. When the beef has 10 mins left to cook, finely chop the spinach leaves. Add the spinach to the slow cooker and carefully stir it through. Place the lid back on for 5 mins to wilt the spinach.
6. Spoon the yogurt into the beef and stir through. Taste the beef and add more salt and pepper if you think it needs it. Divide the Bombay spiced beef curry between 4 warm bowls and serve.
7. On the Hob:
When the beef is browned, lift it out of the pan and pop in a bowl. Add 4 tbsp water to the pan then add the onion. Fry on a medium-low heat, stirring now and then, for 10 mins till lightly coloured.
8. While the onion cooks, dice the tomatoes. Peel and chop the potatoes into 3-4cm-thick chunks.
9. Add the garlic, ginger and chilli to the onion and cook for 2 mins. Add the beef back to the pan, along with any resting juices. Add the tomatoes, potatoes and 1 tbsp Bombay spice mix. Season with some salt and pepper. Pour in 500ml boiling water. Stir well then pop on the lid.
10. Simmer on a medium heat for 40 mins till the beef and potatoes are tender and the sauce thickened and reduced slightly. Stir every now and then and if the sauce starts to look a little dry, add a splash or 2 of water.
11. When the beef has 10 mins left to cook, finely chop the spinach leaves. Add the spinach to the curry and carefully stir it through. Place the lid back on the pan and cook for 5 mins to wilt the spinach.
12. Spoon the yogurt into the beef and stir through. Taste the beef and add more salt and pepper if you think it needs it. Divide the Bombay spiced beef curry between 4 warm bowls and serve.