1½ kg medium potatoes, such as King Edward, cut into wedges
3 tbsp sunflower oil, plus extra for greasing
1 tbsp thyme leaf
2 tsp peppercorns, crushed
Mix together the vinegar, stock, mustard, syrup and olive oil in a large shallow bowl, then grind in some black pepper, but no salt.
Add the steaks and turn to coat. Leave to marinate in the fridge for 1 hr, or preferably overnight.
Heat oven to 200C/180C fan/gas 6. Toss the potatoes in a large bowl with the oil, thyme and peppercorns.
Spread out on 2 greased baking sheets and bake for 10-15 mins until the potatoes are nearly cooked. Remove and leave to go cold.
Open-freeze the wedges until solid, then pack into a large rigid container in layers, interleaving with foil.
Individually pack the steaks into freezer bags – make sure they lay completely flat when you put them in the freezer. Use within 1 month.
To serve, heat oven to 220C/200C fan/ gas 7, with a baking tray inside to warm up for the steaks.
Put the wedges on another large baking tray, spread them apart and season. Bake for 20 mins until golden and crisp.
Unwrap the steaks and brush both sides with oil. Press onto the hot tray and bake for 15-25 mins, turning after 10 mins and testing until hot, to give you medium-rare steak. Serve with the wedges and salad, if you like.