Some Cards

When it gets quiet at the Tea Rooms, out come my scissors and glue for a bit of cut-and-paste action. 

Sweet Potato and Purple Potato Gratin

No need to adjust your colour calibration - some of the potatoes here are indeed purple. If you need to impress anyone, this dish will certainly do it. The contrasting colours and rosette-like appearance pack a punch when brought to the table in its baking dish, and it looks more complicated than it really is. In fact, if you have a mandolin, it can all be prepared in mere minutes. Just be careful not to slice your fingertips off - nobody wants bloody fingertips in their portion of gratin.

The dish was inspired by two events in close succession - the discovery that our local supermarket sold purple potatoes, as well as our recent purchase of Ottelenghi: The Cookbook from a secondhand bookstall in Greenwich Market. Ottolenghi's version calls for just orange sweet potatoes, but I decided we could possibly do one better. If you can't find purple potatoes, than 50% normal potatoes and 50% percent sweet potatoes, or even 100% sweet potatoes, would do just as welll. 

Sweet and Purple Potatoes Gratin 

(adapted from Danielle's Sweet Potato Gratin in Ottolenghi: The Cookbook)

Ingredients

about 750gms purple potatoes

about 750gms sweet potatoes

5 tbsp sage (roughly chopped), plus extra for garnish

6 garlic cloves (crushed)

2 tsp coarse sea salt

1/2 tsp black pepper (freshly ground)

250ml whipping cream

Directions

- Preheat oven to 200 degree C. Wash the potatoes but leave them unpeeled. Slice them into discs roughly 5mm thick.

- Mix the potatoes, sage, garlic, salt and pepper together in a large bowl. Arrange the potato slices in a medium-sized baking dish by taking stacks of them and packing them next to each other*. Any any remaining bits of garlic and sage from the bowl to the potatoes. Cover the dish with foil and roast for 45 minutes. 

- Remove the foil and pour the cream evenly over the potatoes. Roast, uncovered, for another 25 minutes. The cream should have thickened by the end of the cooking time. 

- Garnish the dish with sage, and serve immediately. 

*I arranged the potatoes by placing them first along the outer ring of the dish, then working inwards, to create the rosette shape. There's no need to be too precious about placing the different colours one of top of the other.