Vegan Gratin Dauphinois with Oat Cream

Soak the cashews in cold water for a minimum of 4 hours or overnight.

Drain the cashews and blend with 100ml of the oat milk, 1 tablespoon of the nutritional yeast, the Dijon mustard, and a pinch of salt until completely smooth — no graininess when rubbed between your fingers. Set aside.

Peel and mandoline-slice the potatoes to 2mm thickness. Do not rinse the slices; the surface starch is essential for binding the gratin.

Combine the oat cream, remaining 100ml oat milk, minced garlic, salt, white pepper, nutmeg, remaining 1 tablespoon nutritional yeast, thyme leaves, and cornstarch in a large saucepan over medium heat. Whisk to dissolve the cornstarch.

Add the potato slices to the saucepan and bring the cream mixture to a gentle simmer, stirring carefully so slices do not tear. Simmer for 8 minutes until the liquid has thickened slightly and the potatoes are just beginning to bend without snapping.

Preheat the oven to 160°C fan, or 180°C in a conventional oven, or 350°F. Rub a 28 × 20cm gratin dish thoroughly with the cut face of the halved garlic clove, then brush with the olive oil.

Using tongs, layer the potato slices in the dish in overlapping rows, pouring the cream mixture over each layer as you build. Pour all remaining cream over the top — the potatoes should be just submerged.

Spoon the blended cashew mixture evenly over the surface and spread gently with the back of a spoon.

Cover the dish tightly with foil and bake for 60 minutes until a skewer meets almost no resistance through the centre.

Remove the foil and bake for a further 25–30 minutes until the top is deeply golden and bubbling at the edges.

Rest the gratin uncovered for 15 minutes before serving; this allows the cream to set so slices hold their shape.