In a food processor, or nutribullet or blender, combine the mint, coriander, coriander stalk, ginger, and water until it makes a smooth paste. It's okay if it is a bit watery. Set this aside
Heat 1 tbsp of vegetable oil in a non-stick fry pan or pot until just hot over the lowest heat setting
Add the cumin seeds, asafoetida, and chopped chilli. Make sure you stir using a wooden spoon to ensure the cumin does not burn
Add the potatoes and coat well in the oil and cumin seeds and heat through to develop some colour
Pour in the mint and coriander mixture prepared in step 1 and mix everything through. Cook this until the mixture starts to dry a little as the water evaporates
Add the lemon juice and then the garam masala
Cook the potatoes through, until you see some crisping of the potato skin
Serve hot with some yogurt, fresh mint, some fresh red chilli and some lemon wedges. I love serving this with fresh naan, or papad/poppadum as a main or as a little snack