Pre-heat sauce pan over medium heat. Add butter or neutral oil and allow to heat.
Add shallot to saucepan and sauté until softened and just turning golden. Salt the shallots lightly as they cook. Stir while cooking. If you are using dried tarragon add it now.
Add the white wine to deglaze the pan and allow to cook down until syrupy. A little more than halfway but not completely to the point it’s almost gone. Stir occasionally.
Add the chicken stock and allow to cook down half way. If you’re using homemade stock that has developed gelatin it should start to thicken. If you’re using box stock you may want to bloom a gelatin sheet in the stock before adding to the sauce pan to get the same thickened consistency. Taste and add more salt if needed, but aim for less seasoning as the taste will intensify as it continues to reduce.
Once stock has reduced half way add in the heavy cream. At this point you want to stir consistently to prevent the cream from burning on the bottom. Cook until the sauce reaches desired consistency. Add the fresh tarragon for the last 5 minutes of cooking. If you are using box stock without bloomed gelatin the sauce will not reach an entirely thick consistency, so don’t over-reduce. Aim for about half way. Taste and finish with salt as needed.
