How To Make Celeriac, Potato & Swiss Cheese Gratin

1. Preheat oven 180°C /160°C fan assisted (gas 4).
2. Infuse milk & cream with garlic, thyme & bay over a gentle heat for 2 minutes, season highly with salt & pepper then leave to stand a little before passing through a fine strainer.
3. In a bowl mix together the celeriac, potato & infused liquid then layer into a dish alternating layers with a sprinkling of cheese & liquid until all the potatoes & celeriac is used up.
4. Top with a final layer of cheese & liquid then place in the centre of the oven.
5. Bake for approximately 1 hour 15 minutes pressing gently every after 15 minutes.
6. If the top is getting too dark reduce oven temperature a little.
7. The gratin should be tender when pierced with a skewer.
8. Leave to rest a few minutes before serving.

Note:The gratin can be prepared up to step five in the morning & chilled ready for cooking.