Mixed-Bone Brown Stock

Set the oven to 200 °C, fan.

Fan keeps two trays browning at the same rate. 200 °C fan gives the same browning as 220 °C conventional.

Cut all visible fat off the lamb bones.

Pat the beef bones and the marrow bones dry.

Spread the beef bones and the marrow bones on two roasting trays in one layer.

Cut the onions in half. Keep the skin on.

Cut the carrots into chunks of 50 mm.

Cut the celery into lengths of 50 mm.

Roast the beef bones and the marrow bones for 20 min.

Turn the beef bones. Move the top tray to the bottom shelf and the bottom tray to the top shelf.

Add the mixed bones to the trays. Roast for 10 min.

Spread the tomato paste in a thin layer on the beef bones.

Put the onions cut side down between the bones. Add the carrots and the celery.

Roast for 10 min. Stop when the paste is dark red, before it turns black.

Move all the bones and vegetables into the stockpot.

Pour 250 ml of the water onto the hot trays. Scrape off all the brown residue.

Pour the liquid from the trays into the stockpot.

Add cold water until it covers the bones by 50 mm.

Heat slowly on medium-low heat for about 45 min. Do not let it boil.

Remove the grey foam from the surface as it rises.

Add the peppercorns, the thyme and the bay leaves.

Hold at a light simmer for 10 h with the lid off.

A light simmer is 88 °C to 90 °C. One slow bubble breaks the surface every 1 to 2 seconds. A longer time does no harm.

Add hot water when the bones show above the surface.

Pour the stock through a fine-mesh sieve. Do not press the solids.

Divide the stock into shallow containers. Refrigerate until the fat sets solid.

Remove all of the solid fat from the surface.