Ash-Coated Loin of Venison, Maitake, Red Cabbage, Pistachio, Mastic, and Porcini Jus
For the Beet Ash:
Trim beets, remove tops, scrub under cold running water, and dry on paper towels. Wrap individual beets tightly in aluminum foil. Cover beets with hot glowing charcoal embers and let char overnight. Carefully open foil and transfer charred beets to food processor; process to ash. Pass ash through chinois. Store Beet Ash in airtight container at room temperature.
For the Venison Marinade:
Whisk Beet Ash into oil until combined. Coat venison in ash mixture, cover, and marinate overnight in refrigerator.
For the Porcini Jus:
Preheat oven to 425°F. Lightly coat bones in oil and roast until browned. In large rondeau, heat oil and sweat onions, carrots, celery, leeks, and celery root until carrots are tender. Deglaze with brandy and reduce by three-quarters. Add wine and reduce until about 1 cup liquid remains. Wrap thyme, peppercorns, juniper, and allspice in cheesecloth and secure tightly with twine. Add sachet and bones to rondeau, cover with stocks, and reduce by half. Strain Jus through chinois and season with salt and pepper. Add cherries and porcinis, cover, and steep until completely cooled. Set aside in refrigerator.
For the Red Cabbage Fondue:
In rondeau, sweat cabbage and shallots in butter until cabbage is almost tender. Add honey and cook until honey foams. Deglaze with wine and port. Add cherries, allspice, juniper, and potato. Remove from heat when potato is cooked through and cabbage is tender and glossy. Season with salt and pepper, finish with cherry vinegar, and let cool. Finely chop cabbage mixture, cover, and refrigerate.
For the Rosemary Gel:
Combine rosemary with water and let infuse for at least 15 minutes; the rosemary flavor should be intense. Strain rosemary water through chinois into Vitamix and blend. When vortex forms in center, shear in gellan and blend until dispersed. Pour mixture into pot with sugar and bring to simmer, whisking until sugar dissolves. Transfer to quarter-sheet tray lined with plastic wrap. Let cool until firmly set. Cut into ½-inch cubes, cover, and refrigerate.
For the Pistachio Purèe:
Combine all ingredients in medium saucepan, bring to simmer, and cook until potatoes are tender. Blend in Vitamix until smooth. Transfer to squeeze bottle or pastry bag and refrigerate.
For the Mastic Cream:
Combine all ingredients and simmer 3 minutes. Strain through chinois into eighth-sheet tray and let cool completely. Transfer to Vitamix and blend until smooth. Transfer to squeeze bottle or pastry bag and refrigerate.
For the Pistachio Crumble:
Combine pistachios and cherries in food processor and pulse to coarse crumb. Set aside in airtight container.
To Assemble and Serve:
Let Rosemary Gel, Pistachio Purée, and Mastic Cream come to room temperature. Reheat jus and cabbage. Season venison with salt and pepper and pan-roast, basting in butter and thyme, to desired temperature. Season maitake and sauté in oil. Plate venison on cabbage and arrange maitake around them. Squeeze or pipe a few dollops of Pistachio Purée and Mastic Cream around venison. Add a couple cubes Rosemary Gel and sprinkle Pistachio Crumble on plate. Garnish with onion petals and chervil. Finish with Jus.