On the stove top, heat the butter, onion and garlic until the onions are translucent.
Whisk in the flour and form a rue.
Add the rue to a 5 qt or 6 qt slow cooker.
Mix in chicken, chicken broth, potatoes, peas, carrots, rosemary, thyme, salt and pepper.
Cover and cook on HIGH for 3 hours.
Remove the chicken and shred. Return the shredded chicken to the slow cooker.
Mix in the heavy cream and heat for another hour on high.
Serve with biscuits.