I'd probably start by sauteing some onion in butter until softened. Add the garlic until fragrant., add the herbs. Add some flour, maybe a couple Tbsps, and cook out the raw flour taste, basically making a roux. Add the wine stirring in well and cooking for a few minutes, then the warm stock, a little at a time until you get the consistency you want for the sauce, stirring often. Personally, I would add some rubbed sage or poultry seasoning as well.
Hope this helps and welcome to DC!
Emeralds are real Gems! C. caninus and C. batesii.