Miso + mustard potato gratin with TLC oil
This potato gratin is one of my favourite recipes, a go-to side dish for all occasions. It’s remarkable that this is vegan, as the creamy umaminess somehow surpasses your classic cheese gratin. This comes from the combo of coconut milk, miso and mustard that bathe the potatoes as they bake, and the secret lift from the TLC (thyme, lemon + chilli) oil that makes it soar.
Top Tip - the potatoes are best sliced with a mandoline, but you can alternatively use a sharp knife - just be careful to ensure the potatoes are sliced very thinly.
hands-on time
30 minutes
serves
6 as a side
1 hour 45 minutes
total time
Ingredients
Gratin
2 tbsp olive oil
1 red onion, peeled and finely sliced
3 cloves garlic, crushed
1 tbsp yellow mustard seeds
2 tsp ground cumin
250ml coconut milk
250ml vegetable stock
1 tbsp dijon mustard
1 ½ tbsp Shiro (white) miso paste
2 tbsp finely chopped thyme leaves
½ tsp cracked black pepper
1kg waxy potatoes, peeled and cut into thin 3mm-thick slices (e.g. with a mandoline)
TLC oil
60ml olive oil
2 cloves garlic, finely grated
2 tsp chilli flakes
finely grated zest of 1 lemon
1 tbsp thyme leaves
large pinch of sea salt
Method
Preheat the oven to 180°C fan-forced (200°C conventional). Brush a medium baking dish (approx. 28cm x 20cm) with olive oil.
First make the TLC oil. Place the oil in a small saucepan over medium heat, and warm for 5 minutes. Remove from the heat and stir through the garlic, chilli flakes, lemon zest, thyme and sea salt. Cover with a lid and set aside to steep and allow the flavours to infuse into the oil for a minimum of 1 hour (the longer the better).
For the gratin, place the oil in a medium saucepan over medium heat. Once hot, add the sliced onion and saute for 8 minutes until starting to soften nicely. Add the garlic, mustard seeds and ground cumin, and cook for a further minute, tossing through the onions. Pour in the coconut milk and vegetable stock. Bring to the boil then remove from the heat. Add the mustard, miso paste, chopped thyme and black pepper, stirring until the miso has dissolved. Adjust seasoning to taste with sea salt if needed.
Arrange a slightly overlapping layer of sliced potatoes in the bottom of the baking dish. Spoon over some of the warm gratin sauce and onions to cover, then repeat, layering the sliced potatoes and sauce until it is all used up, finishing with a layer of sauce to bathe the potatoes. Cover tightly with aluminium foil and bake in the preheated oven for 40 minutes. Remove the foil and bake for a further 35 minutes, until the top is golden, crisp and bubbling and the potatoes are cooked through. To finish, if desired, change the oven function to grill and grill the top of the gratin for a few minutes to get it extra golden and crispy.
Remove from the oven, leave to cool for 10 minutes, then spoon over the TLC oil, including all the delicious bits. Serve warm.