Cauliflower, Cheddar and Potato Gratin

Instructions

1. 1

   Heat the conventional oven to 190°C / 375°F with a rack in the middle. Grease a 3.5–4 litre baking dish, approximately 33 × 23 cm and at least 6 cm deep, with the olive oil.

2. 2

   Scrub the potatoes and slice into even 2–3 mm rounds. Cut the cauliflower into small, approximately 2 cm florets, using 600 g of trimmed florets. Finely chop the garlic. Grate the cheddar, choosing cheese labeled suitable for vegetarians.

3. 3

   In a bowl, whisk the cornstarch with 100 ml of the cold milk until smooth. Whisk in the remaining 600 ml cold milk, garlic, mustard powder, salt and pepper, then stir in 175 g of the cheddar.

4. 4

   Arrange the potatoes and cauliflower evenly in the dish, separating any thick stacks of potato slices. Pour the cold milk-cheese mixture over them. Cover tightly with foil and bake at 190°C / 375°F for 70 minutes. Carefully lift the foil away from your face and test several potato slices in the centre with a knife; they should be almost tender. If still firm, cover again and bake for another 10 minutes before continuing.

5. 5

   Remove the foil and scatter the remaining 75 g cheddar evenly over the top. Bake uncovered at 190°C / 375°F for 20 minutes, until golden, bubbling in the centre and completely tender when pierced.

6. 6

   Rest for 10 minutes before dividing into four generous portions; this resting time is included in the cooking time.