Creamy Potato, Quinoa and Caramelised Onion Gratin

A creamy potato gratin is a classic dish to have in your vegan repertoire for those nights you are craving something warm, rich and heartening.
Everything bubbles down together gloriously in the oven, underneath a lovely crispy top. The quinoa and caramelised onion make delicious additions and elevate this recipe from a side dish to centre stage as a complete meal.
If you want to speed things up a bit, you can use store-bought caramelised onion instead.
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  • 2 tbsp olive oil
  • 1 red onion peeled and sliced finely
  • 1 tbsp brown sugar
  • 1 ½ tsp salt
  • 6 (1 kg) medium potatoes any variety, washed and peeled
  • 400 ml coconut milk
  • 250 ml plant-based milk we used oat milk
  • 2 tbsp wholegrain mustard
  • Pinch ground nutmeg
  • ½ tsp smoked paprika
  • 4 cloves garlic minced
  • 4 sprigs fresh thyme finely chopped
  • 2 tbsp nutritional yeast
  • 2 cups / 370g / 13 oz cooked quinoa


  • Preheat the oven to 200 degrees Celsius / 390 Fahrenheit.
  • To make caramelised onion, add oil to a pot and heat on medium. Add sliced onions and cook gently for 2 minutes, until softened.
  • Add brown sugar and ½ tsp salt. Stir to combine. Continue cooking gently on low to medium heat, stirring occasionally, for a further ten minutes. Set aside once finished. If you are using store bought caramelised onion, skip this step.
  • Meanwhile, while onions are cooking, slice the potatoes as thinly as possible into rounds.
  • In another pot, combine all remaining ingredients. Bring to the boil, stirring occasionally. Turn off the heat and set aside.
  • Brush a skillet or shallow baking dish with some olive oil. Place the potato slices evenly across the bottom of the skillet in layers. After 3 layers, pour in enough of the milk and quinoa mixture to cover the potatoes. Spoon over the caramelised onion. Layer the rest of the potatoes and pour in the remaining quinoa mix.
  • Tap the skillet gently on the bench to remove any bubbles and spread the liquid through the dish evenly.
  • Place in the preheated oven for approximately 1 hour, or until potatoes feel tender when tested with a sharp knife. Check after 40 minutes and cover with a lid or foil if it’s getting very browned.

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