Slow Cooker Coconut Chicken Curry

Boneless skinless chicken breasts cut into large chunks
1 onion, peeled and halved
2 cloves garlic peeled
1 bell pepper seeded and quartered
1 can tomatoe paste
1 can coconut milk
1 1/2 tsp. Salt
1 tbs. Curry powder
1 tbs. Garam masala
2 whole dry red chili peppers (optional) I left them out.
2 tbs. Water
2 tbs. Cornstarch
1 bunch coriander (optional, for decoration)

Place chicken cubes in slow cooker. Place the rest of the ingredients (except chili peppers,cornstarch, water and coriander) in food processor and process until smooth. Pour over chicken and mix well, add hot peppers if using. Cook on low for 6 hours. An hour before done mix cornstarch and water and pour in crockpot. Stir to combine. Finish cooking. Serve over basmati rice with chopped coriander if desired.