MAKE the blanquette, once the mushrooms are pickled. In a medium saucepan, bring the mushroom stock to a boil. Reduce the heat to a simmer and cook until the liquid has reduced to 1 cup, 15 to 20 minutes. Transfer the reduced mushroom stock to a blender. While the motor is running, add the remaining ingredients, replace the lid and blend on high for 2 to 3 minutes. Transfer the blanquette back to the saucepan and warm over low heat, 1 to 2 minutes. Don't turn up the heat too high or the mixture will overcook and the eggs will scramble.