Start by heating the oil in a pan over medium heat. While it’s warming, dice that onion into small pieces. Once the oil is shimmering, toss in the diced onion and cook until it’s soft and translucent.

After that, stir in the garlic and ginger. These ingredients add aroma and flavor that will kickstart your curry. Cook for about one minute until fragrant—delicious aromas are already filling the kitchen!

Now it’s time for the spices! Add the curry powder, ground coriander, ground cumin, paprika, and cinnamon to the pan. Stir them into the onion mix for about 30 seconds. This crucial step helps activate the spices, releasing their full potential.

Once blended well, remove the mixture from heat. This will be the flavor-packed base for our curry!

Transfer the cooked onion and spice mixture to your slow cooker. Now, add the diced chicken breasts, ensuring they are well coated. Pour in the chicken stock, passata, tomato puree, and coconut milk. Sprinkle in the sugar and salt, and give everything a good stir to combine.

Set your slow cooker to low and let it work its magic. Cook for about 6-8 hours, or on high for 4-5 hours. This is the part where patience becomes a virtue—though you could easily pop your head in every now and then for a sneak peek at the deliciousness.

About 30 minutes before serving, check your curry. If you want it thicker, prepare a cornstarch slurry by mixing the cornflour with cold water. Stir this into the curry and let it cook a bit longer until it thickens to your desired consistency.

Before serving, taste and adjust seasoning as needed. Maybe add a pinch more salt or a little squeeze of lime if you're feeling frisky.

Serve the curry over a bed of fluffy pilau or boiled rice. Garnish with fresh coriander and a side salad of tomatoes and onions. Dive in with a piece of naan, and enjoy every spoonful!