Whisk together stock, thyme, pepper, garlic, salt, and xanthan gum in a small saucepan. Add butter. Turn the heat to medium.
Bring to a boil and reduce heat to low. Simmer for 1-2 minutes until thickened. Remove the gravy from stove and cool for 5 minutes.
Divide gravy between 4 small sauce cups. Place next to sliced chicken in large compartments of 4 MPOF white containers. Divide cauliflower rice and broccoli between small compartments.