Pour a couple cups of boiling water over the mushrooms to rehydrate them. Chop and shred the other ingredients while the mushrooms are softening. When they are rehydrated, chop them fine. Reserve 1 cup of the soaking water.
Heat 3 tablespoons of the butter in a medium pot over medium-high heat. Sauté the onions and the mushrooms until the onions are soft and starting to brown, about 5 minutes. Add the garlic and the barley and stir well.
Stir in the cup of mushroom soaking water, then add the herbs and juniper, if using. Stir constantly until the water has mostly been absorbed, then add a cup of the stock and repeat.
Keep this process up until the barley is tender. Once you have a couple cups of liquid absorbed, you can drop the heat to medium and slow down on the stirring. You still need to stir often, just not constantly.
When the barley is tender, stir in a little more stock, the shredded grouse and the cheese. When that's incorporated, mix in the last tablespoon of butter. Serve garnished with chives.