I tossed this together using what I had on hand and it turned out beautifully. This would make a wonderful entrée for any holiday gathering.
I have not included any salt in this recipe as the onion soup mix provides enough to start. You can of course adjust if more is needed.
The gravy is totally optional as the turkey is quite moist on its own. Learn more about making a basic roux for gravy here.
Place sliced onions in the bottom of the cold slow cooker. Place the cold turkey tenderloins on top of the onions.
Dissolve Better than Bouillon in hot water or substitute one cup of chicken or beef broth. Add to slow cooker with soup mix, sage and thyme (**or poultry seasoning.)
Cook on low for 6 hours making sure that the internal temperature when finished is 165° F.
In a skillet, melt the butter over medium high heat and slowly sprinkle in the flour. Use a wooden spoon to whisk constantly, scraping the skillet, to dissolve all flour and form your roux. Keep whisking and cook for 3-5 minutes until all flour is incorporated and the roux is pale blonde in color.
Strain one cup of the cooking liquid from the slow cooker and pour into the skillet. (If you do not have a full cup, use water, broth/stock or milk to get to the full cup.) Keep whisking until combined. Once everything is incorporated and bubbling, reduce the heat to a simmer.
Keep stirring and allow the gravy to cook until it reaches your desired thickness. If it's too thick, add a bit more cooking liquid/water/broth/milk to get it just right. Taste and adjust seasonings as needed.
*Substitute one cup of chicken or beef broth for the cup of water and Better than Bouillon.
**You may substitute 2 teaspoons dried poultry seasoning for the sage and thyme.