Here is the recipe I promised from the Gravy Train Blog for a very rich and easy to make sauce..I used chicken stock, but for darker color you may use beef stock or turkey stock..

roux:

4 Tbsp. butter

4 Tbsp. unbleached all purpose flour

1 1/2 cups heavy cream

1 1/2 cups stock

Salt & Pepper  To taste

melt butter, add flour and cook for 3-4 minutes until it comes together…Let cool for 10 minutes..Add heavy cream, stock ,

salt & pepper to  saucepan, add any fresh herbs desired bring to boil, and slowly add roux little by little till thick enough..You want this one slightly thicker because you will add turkey meat juices to it for more flavor which will thin it out..I used fresh rosemary, sage & thyme..

stock-http://amzn.to/21cbsbv