Slow cooker creamy lemon chicken

Name: Slow cooker creamy lemon chicken
Ingredients: 4 chicken breasts, skin removed and boneless; large pinch dried thyme; 1 tbsp sunflower oil; 20g/¾oz butter; 2 large garlic cloves, crushed; 1 medium lemon, finely grated zest only, plus extra to serve; ½ tsp ground paprika (not smoked); 300ml/10fl oz hot chicken stock, made with 1 stock cube; 1 tbsp cornflour; 5 tbsp double cream; 35g/1¼oz Parmesan, finely grated; salt and freshly ground black pepper; chopped fresh thyme or parsley, to garnish; freshly cooked rice or potatoes and vegetables, to serve