Pan-fried flank with shallot, mushroom and Madeira sauce

1.For Madeira sauce, preheat oven to 250C. Combine trimmings, marrow and garlic in a roasting pan and roast until brown (30-40 minutes). Transfer to a saucepan with thyme, Madeira and 1 litre water. Bring to the simmer over medium heat, reduce heat to low-medium and cook until reduced by one-quarter (2 hours). Strain (discard solids), then refrigerate until chilled (overnight). Skim fat from surface (discard), then reduce stock over medium-high heat by three-quarters (20-30 minutes).

2.Meanwhile, for Anna potatoes, preheat oven to 200C. Heat 60ml clarified butter in a 20cm cast-iron frying pan over medium heat, reduce heat to low, then, working quickly, layer potato in pan in concentric circles covering the base and overlapping slightly, then repeat, layering in the opposite direction, scatter with thyme, brush with a little clarified butter, season to taste. Repeat with remaining potato, butter and thyme, pour over any remaining butter, transfer to oven and bake until starting to soften (15-20 minutes). Remove from oven and press down firmly with the base of a saucepan to compact, then return to oven and bake until edges start to turn golden (10-15 minutes). Press again, then cook until golden and tender and loose in the pan (10-15 minutes; see note). Press again, then set aside and keep warm.

3.Meanwhile, heat a large frying pan over high heat, add butter, shallot and garlic, cook until butter is foamy and shallot is tender (4-5 minutes), add mushroom, stir occasionally until golden (4-6 minutes), season to taste and keep warm.

4.Heat oil in a separate large ovenproof frying pan over high heat until smoking, add steaks and sear until browned (1-2 minutes each side). Transfer to oven and roast until rare (5-6 minutes), then transfer to a warm plate to rest (5-10 minutes).

5.Deglaze pan with Madeira until almost evaporated, then add Madeira sauce and cook until reduced slightly (3-5 minutes). Strain through a fine sieve and serve over sliced flank and mushrooms, topped with cress, with Anna potatoes.