Add butter to a pan on low to medium heat and let that melt. Add onions and Sautee. Add the flour and whisk well. Then add the chicken stock and turn up the heat to medium/high and stir this while it thickens. After it thickens let it cool a bit and then add the cream, salt, and pepper. This will not be as thick as the cream of chicken from the store, but you can cook it down or add 1 to 2 Tbsp. of flour at the time called for in the recipe. You could also add flour to some water and whisk this up and then add it to the cooked cream of chicken. This will ensure you don't get lumps by just adding flour.
