- Step 1
Heat 1/2 the oil in a large frying pan over medium heat. Add onion. Cook, stirring, for 5 minutes or until softened. Transfer to slow cooker.
- Step 2
Heat remaining oil in the pan over medium-high heat. Cook chicken, in batches, for 2 minutes each side or until just browned all over. Add to slow cooker.
- Step 3
Add celery, carrot, garlic, passata, stock, oregano and sugar to slow cooker. Stir to combine. Cover. Cook on high for 4 hours (or low for 8 hours), adding mushroom in the last 30 minutes of cooking. Season.
- Step 4
Add olives to the remaining chicken mixture. Stir to combine. Serve cacciatore with beans and crusty bread.
Once cool, transfer chicken and sauce mixture to an airtight container. Refrigerate for up to 3 days or freeze for up to 3 months.