Method

Start by pre-heating the oven to 180° (356F). While the oven is heating up add the onions, garlic dried chillies, two of the fresh chillies, ginger and lemon juice to a blender, with a little water. Blend this until smooth.

Chop the potatoes in half and the add them to mixing bowl with the broccoli, the olive oil, salt, pepper and 1 tablespoon of garam masala. Toss to coat everything, and then spread out on a baking tray and bake in the oven for 25 - 30 minutes.

Heat a pan over a medium-high heat. Once hot add some vegetable oil and then the cumin and fenugreek seeds. Cook these until fragrant, moving the seeds around the pan to stop them burning. This should only take 30 seconds to a minute

Next, add the blended onion mixture and cook for about 5 minutes, stirring to prevent it burning to the pan. Add the turmeric, paprika and remaining 3 tablespoons of garam masala to the onion mix and stir in to combine. 

Add in the chopped tomatoes, then fill the can with water and pour this in as well. Stir everything together. Chop the pepper and mushrooms and add these to the pot, as well as the remaining 2 fresh chillies. Leave to simmer for 35 minutes. 

Once the potatoes and broccoli are ready take them out of the oven and add them to the curry.

Add the fenugreek leaves and fresh coriander for the last couple minutes of cooking.