Best ever authentic curry recipe

I had struggled with home made curry - none of the pastes or spice mixes ever tasted quite 'right' - until I got this recipe off a work colleague from Gujerat. The secret is in the method - you'll need a hand blender.

Best ever authentic curry recipe:

Ingredients (for two)
4 chicken thighs, skinned (or any meat)
1 tablespoon olive oil
1 tablespoon butter
1 large onion, halved and finely sliced
Half a thumb-sized piece of ginger, finely chopped
2 whole green chillies, or more to taste, finely sliced (Indian ‘finger’ chillies are best, but Thai will do)
4 cloves of garlic, finely chopped
1 400g tin of chopped tomatoes
salt
¼ teaspoon ground cumin
¼ teaspoon ground fenugreek
½ teaspoon ground turmeric
½ teaspoon cayenne pepper
small pinch garam masala

Method
Take a heavy based saucepan with a tight-fitting lid. A Le Creuset casserole dish is perfect.
Fry the onion in the oil and butter until translucent, stirring frequently.
Add the ginger, chillies and garlic, and cook for a minute or two longer, still stirring.
Add the tomatoes and stir.
Liquidise the mixture to a fine puree (a hand blender is perfect for this).
Add the cumin, fenugreek, turmeric, cayenne pepper and salt (but not the garam masala).
Add the meat and bring to a gentle simmer.
Simmer with the lid on, on a low heat for 45 minutes to an hour (or in the oven at 150C). Check it occasionally and stir.
The dish is cooked when the oil rises to the top of the sauce.
Add the pinch of garam masala right at the end of cooking.

NB:
Don’t be tempted to add any extra water - it doesn’t need it.
Don’t be tempted to fry the spices in with the onions, garlic and ginger – they’ll go bitter.
Add the garam masala at the end, just a tiny pinch and then taste it. You can always add more.
De-seeding chillies is for wimps.

I've got some authentic Maldivian curry recipes which I'll post up at some point - a nice mixture of Indian and Thai styles