1 1/2teaspoonsfine saltif you’re using table salt, taste as you go
1teaspoonground nutmegoptional
Generous cracked pepper
Balsamic vinegar or lemon juiceto taste (to replicate the acidity of hard cheese)
Seasoningto taste
FOR THE VEGAN POTATO AU GRATIN
1kgall rounder potatoesskin on (I used Sebago, see note)
500gsweet potato1 large, skin on
150gvegan stuffing(scroll up for recipe intro)
Instructions
TO MAKE THE STUFFING CRUMBLE
To make the stuffing crumble, preheat the oven to 180 degrees Celsius. Place 150g of stuffing (recipe link above) on a baking tray, spread out.
Cook the stuffing for anywhere from 10-30 minutes, depending on how much you cooked it beforehand. It needs to have crunchy edges and be mostly dry.
Allow it to cool, and then pulse it very quickly in your food processor. You could also chop it by hand. Set aside (on a plate if it’s still warm – bowls trap heat more.)
TO MAKE THE GRATIN
To make the roux, add the olive oil to a large saucepan and heat until warmed through. Add the cornflour, whisking thoroughly to combine. The mixture should begin to bubble and congeal straight away.
As soon as it has, add half the plant milk, and whisk well to combine. Add the other half, along with the nutritional yeast.
Continue to stir over a low medium heat, until the mixture has thickened considerably. You’re after the consistency of cream, or a bit thicker.
Add generous seasoning – 1/2 teaspoons good quality salt, 1 teaspoon nutmeg, loads of cracked pepper, and balsamic or lemon juice, to taste. I can’t stress enough – season to your own taste and season very generously.
TO FINISH
Preheat the oven to 180 degrees Celsius.
Use a mandoline to finely slice all the potatoes. Place them into a large mixing bowl.
10. Pour the roux over the potatoes and (provided the roux isn’t hot) use your hands to ensure all the potatoes are covered in roux.
11. Decant the mixture into your cooking vessel of choice, and arrange the potatoes disks facing up. Pop in the oven.
12. Cook the gratin for anywhere up to an hour or so, until the potatoes are cooked and the top golden. If at any point the top is getting too dark, place a foil tent over it. This will allow it to continue cooking without excessive browning.
Around 15-20 minutes before you pull it out, sprinkle the stuffing crumble over the top. You can also just sprinkle it as a topping at the end, if you're worried about it getting burnt.