Step 1In a large saucepan, heat the oil over medium-high heat until hot. Stir in the turkey pieces, turning until browned on all sides, 5 to 7 minutes.
Step 2Add the onion, carrot and celery, stirring until softened and lightly browned, 8 to 10 minutes. Stir in the tomato paste, cooking until it darkens, 1 to 2 minutes. Stir in the wine, scraping any flavoring from the bottom and sides of the pan. Add the broth, parsley, thyme, bay leaf and peppercorns. Bring the mixture to a boil, then reduce the heat and very gently simmer for 45 minutes to make your stock.
Step 3Remove from heat and strain the stock into a large measuring cup, preferably fitted with a fat separator, discarding the solids. Skim and discard the fat from the stock.
Step 4In another saucepan, melt the butter over medium heat. Add the flour and cook, stirring to form a roux. Slowly add the stock, whisking to incorporate it with the roux and prevent any lumps. Bring the mixture to a gentle simmer and cook, stirring frequently, until thickened and the gravy is reduced to about 6 cups, 20 to 30 minutes. Season to taste with salt and pepper. Serve warm.