Brown chicken in butter (3–5 mins each side)
Add shallot, garlic, and rosemary; cook for 2 minutes
Add broth, lemon zest, salt, and pepper
Cook on high for 3–4 hours or low for 6 hours
Remove chicken and keep warm
Transfer juices to skillet (or sauté mode)
Stir in cream and cornstarch slurry
Simmer for 5 minutes until thickened
Pour sauce over chicken and serve
