Use this chicken jus to prepare chef Daniel Humm's Loup de Mer.
Preheat oven to 375 degrees. Spread chicken wings in a single layer on 2 large rimmed baking sheets; roast in oven until golden brown, 1 hour and 15 minutes to 1 hour and 30 minutes, turning every 30 minutes.
Heat oil in a 20-quart stockpot over high heat. Add onions, carrots, celery, leeks, and celery root; cook stirring until caramelized, 10 to 15 minutes. Add tomato paste and cook, stirring until caramelized, 5 to 7 minutes. Add wine and cook until thick and syrupy.
Place thyme, bay leaves, and peppercorns in a piece of cheesecloth; using kitchen twine, tie to enclose. Add cheesecloth packet to stockpot along with chicken wings and feet. Bring to a simmer over medium heat; simmer, uncovered, for 5 hours, skimming off impurities and fats that rise to the surface every 30 minutes. Strain through a fine mesh chinoise sieve into a large saucepan; simmer until reduced to 4 cups. Strain again and use immediately or let cool completely before storing in an airtight container, refrigerated, until ready to use.