Place the chicken thighs in the slow cooker and sprinkle over the salt and pepper.
Dice the onion and crush the garlic and add to the cooker along with the sliced, pitted olives.
Sprinkle over the dried basil, oregano and sugar and pour over the chopped tomatoes, passata, and the stock cube dissolved in the hot water. Then add the tomato paste.
Stir everything through well and set the slow cooker to low and leave for 8 hours or high for 4 hours.
Approximately 15 minutes before cooking time has ended, cook the pasta in a pan of boiling water on the hob with a little salt. Check the manufacturers instructions for the exact recommended cooking time.
Once the chicken marinara sauce has cooked, take two forks and roughly shred the softened chicken into the sauce. Then add the roughly chopped fresh basil and stir through well.
Add the cooked pasta to the slow cooker pot and mix well with the sauce to ensure the pasta is fully coated.
Serve immediately with fresh Parmesan cheese.
It's worth investing in good quality canned tomatoes for this recipe to ensure that you get a natural softness and sweetness to the sauce, otherwise the amount of sugar that will need to be added may increase.
Similarly, if you find that the tomatoes used cause the sauce to be slightly acidic, add a few tablespoons of milk to neutralise this.