1. To spatchcock: Turn the squab backside up, cutting along either side of the spine. Save backbone for jus.
2. Flip squab over and open it like a book. Press firmly on the breastbone to flatten.
3. Season squab liberally inside and out with shio koji. Refrigerate uncovered on a rack or baking sheet for at least 8 hours/overnight to let the skin dry. Let sit at room temperature up to 1 hour before cooking.
4. Prepare an open grill for indirect cooking over medium-high heat; oil grates.
5. Sear squab on the hot side of the grill, covering them between turns, 1-2 minutes per side. Move squab to the cool side of the grill, cover and cook, turning occasionally, until a thermometer inserted into breast registers 130-135F for medium-rare.
6. Place aside and tent with foil to rest and keep warm.
Grilled Cultivated Mushrooms
1. Prepare an open grill for medium-high heat. Toss mushrooms with garlic and extra virgin olive oil in a mixing bowl. Season with salt and pepper to taste.
2. Grill mushrooms in a fine mesh sieve or in a grill basket, turning occasionally (or shaking basket to turn), until tender and lightly charred, about 5 minutes.
3. Transfer mushrooms to a platter; finish with parsley and lemon juice.
Mountain Huckleberry Jus
1. In a stainless sauté pan, roast the squab bones with shallot and garlic until golden brown. Deglaze with the red wine and cook uncovered until wine is reduced to a syrupy consistency that measures about 120g in volume, about 40 minutes.
2. Add reduced wine, lemon thyme and stock to saucier. Continue to cook, adjusting heat to maintain a simmer and occasionally skimming fat and impurities from the surface of the liquid with a ladle until it has darkened in color and thickened to a sauce-like consistency ( reduced to about 400g), about 50 minutes.
3. For glossy jus with few impurities in it, midway through reducing, strain jus through a fine-mesh strainer into a smaller saucepan and continue to reduce until liquid has achieved proper consistency.
4. Using a spoon, test the consistency of sauce. The jus should coat the back of a spoon when dipped in it, and when you drag a finger over the spoon, it should leave a clear path.
5. Season jus with black pepper, shio koji, black garlic cloves and black garlic vinegar, adding 15g at a time and stirring to incorporate into the sauce until desired flavor is reached.
6. Lastly add the butter gradually to emulsify and then the huckleberries just before serving. Jus can be used right away or cooled and refrigerated in an airtight container until ready to use.