Place the Potato in a pan of salted water.
Bring to the boil and cook for 6–8 minutes until just tender.
Drain and set aside.
Heat the Olive oil and Butter in a pan over medium heat.
Add the White onion and cook for 8–10 minutes until softened and lightly caramelised.
Add the Garlic, Fresh ginger, Ground cumin and Turmeric powder.
Cook for 1 minute until fragrant.
Add the Potato and stir well to coat in the spices.
Cook for 3–4 minutes.
Add the Baby spinach, Spinach purée and Chopped tomatoes.
Add the Green chilli if using.
Stir well and simmer gently for 10 minutes.
Add the Garam masala and Fenugreek leaves.
Cook for a further 2 minutes.
Season with Sea salt to taste.
Serve immediately.