In a heavy bottom skillet, over medium heat, add your butter. Let melt for a few seconds, and then add your chicken breast chunks. Season with salt and pepper.
Stir in the roasted garlic and cook for a few minutes more. Add in your heavy whipping cream and chicken broth. Stir to mix ingredients together, and then add in your xanthan gum. Simmer for about 5 minutes to let thicken.