Heat
the oven to 400F. Lightly oil sheet pan and place in the oven to heat. Place the
bones on the sheet pan and roast for 30 minutes, turning occasionally. Paint the
bones with a thin layer of the thinned tomato paste, and roast for an additional
30 minutes, turning occasionally, until evenly browned.
Place the bones in the stockpot and cover with cold water. Bring to a boil, and
then lower to a simmer. Skim any scum that forms on the surface gradually as
needed.
Drain and reserve the fat from the pan; deglaze the pan with water and add to
the stockpot. Continue to simmer the stock for 6-7 hours, skimming as needed. If
necessary, you may add more hot water to keep the bones covered.
Toss the mirepoix with the fat and brown in the oven. Add the browned mirepoix,
tomatoes and sachet to the pot. Simmer for another 1-2 hours.
Strain the stock through a china cap layered with cheesecloth, and cool the
stockpot in an ice-water bath. Transfer to a container and refrigerate
overnight; the next day, skim off all the fat that's risen to the surface. Makes
about one gallon of stock.