This is another dish that you can use all your leftovers for. It's so easy - you can make a strong, fragrant curry or just a delicate one depending on what and how many spices you put in. For the sauce, I range from using tinned tomatoes to fresh tomatoes and also whether to use coconut milk or cream. You can experiment with all of these and much more. Even ground almonds make a great addition.
Experimenting and diverting away from recipes is the key here. You won't learn if you don't make mistakes. I've made curries too spicy, too hot, too rich but whatever I do, I always add too much so I've learned to tone down and perfect flavours to my own taste. I personally love cardamon pods and I'm not that mad on cumin seeds so I use more of one and less of the other but someone else might be the other way round; it's all personal.
By the way, this is my own recipe that I've invented - I've got no idea whether it's the way to make curries but I think they taste lovely and it's all fresh and healthy. Spices are the best way of adding flavour without the usual fattiness of butter or cream (like my Nan used to do with everything!)
In general, I start with the spice mix. I tend to mix a teaspoon of each of the following: cumin seeds, fenugreek seeds, fennel seeds, coriander seeds, turmeric powder with 6 cardamon pods and 3/4 cloves. I crush the green cardamon pods to get the black seeds inside as the skin isn't pleasant to eat. So, fry all the spices together (minus the turmeric powder) for 2-3 mins on a hot pan until you can smell them and they're slightly browner than before. Tip them all in a mortar and pestle and grind with a teaspoon of salt until formed a powder (preferably use man with a strong arm like I do!) or you could use one of those special spice grinder machines but I like doing it by hand. Once the curry powder is fine then put aside.
Next, brown off whatever meat you fancy in a large pan (I've used everything from balled up sausage to chicken to pork shoulder to beef neck). When browning meat, don't let the meat touch other pieces as it will create steam which will then start to braise the meat and not brown properly. Brown meat in batched if necessary.
Take out the meat and fry diced onions (2 medium) with 3 cloves of crushed garlic, diced carrot (2 large), and anything else you fancy (maybe peppers etc) in the remaining meat juices. I then add a teaspoon of nigella and mustard seeds and then let them pop for a bit (if the pan is hot enough then they pop around the pan). Make a well in the vegetables and add the curry powder and fry this off for a few minutes. Add the meat back in and stir. Add the turmeric and stir. All this should be done on a medium heat. Then add tomatoes (2 tins worth so you could do a mixture of chopped fresh and tinned if you like) and then turn heat down to simmer. You might need a little more water if you want to simmer it for longer. I like to add fruit to my curries (chicken and mango goes down a storm) after it's simmered for 20 minutes. Allow the tomatoes to thicken up and all the spices to come together. At the end you could add a bag of spinach straight in and stir in, as well as cashews, flaked almonds, or whatever you fancy (the picture in the pan is when the spinach is wilting withing the finished curry - it take seconds).
Serve with turmeric rice (rice boiled with veg stock and teaspoon of turmeric) and a sprinkling of coriander leaves.
If you want to make a creamier curry then make it less spicy and add more coconut cream than tomatoes. The main thing is to experiment and find what your taste buds like the best. Have fun creating!