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Sweet Potato, Caramelized Onion and Mushroom Tart

This show-stopping, vegetarian main is the perfect way to celebrate family, friends, and loved ones all winter long, any time of day. Gluten free and vegan, this can be shared around many tables, regardless of dietary allergies or preferences, and is a way to gather and nourish together.

Sweet Potato, Caramelized Onion and Mushroom Tart



  • ½ cup / 75g raw, unsalted sunflower seeds
  • 1 ¼ cup / 200g buckwheat flour
  • ½ tsp fine grain sea salt
  • 2 tsp. fresh rosemary or 1 tsp. dried rosemary
  • ¼ cup / 60ml coconut oil, very cold
  • 1 Tbsp maple syrup
  • ¼ cup / 60ml ice water, plus more if needed


  • 1-2 small to medium sweet potatoes 1 lb. / 500g
  • a pinch sea salt, to taste
  • 1 Tbsp. cold-pressed olive oil, plus more for finishing
  • ½ tsp. fine grain sea salt
  • 2 Tbsp. coconut oil
  • 2 medium red onions
  • ½ lb. / 250g oyster mushrooms
  • 1 Tbsp. balsamic vinegar
  • cracked black pepper, to taste
  • a few sprigs fresh thyme for cooking, plus a couple for garnish


  • Preheat the oven to 375°F / 190°C.
  • Make the crust: In a dry skillet over medium heat, toast the sunflower seeds until golden and fragrant. Remove from heat and place in a food processor. Let cool for a few minutes, then blend on high until the seeds resemble sand (do not over process or you'll end up with sunflower seed butter!). Add the flour, salt, rosemary, coconut oil, maple syrup, and ice water, and pulse until everything is well incorporated, and the dough hold together. If it is too dry, add a little more water, a tablespoon at a time until it binds.
  • Press the dough down very firmly into the base and up the sides of a 8" / 22cm tart pan. Prick the crust all over with a fork. Bake the crust for 15-25 minutes until golden and crisp. Let cool completely.
  • While the crust is baking, scrub the sweet potatoes well, roughly chop them (leave the skin on) and place on a baking sheet. Place them in the oven below the crust until the crust is finished, remove crust and let the potatoes continue to roast until they are tender, about 20 minutes total.
  • Remove the sweet potatoes from the oven and transfer them to a food processor. Blend on high until smooth and creamy. Add a touch of salt, the olive oil, blend again, and season to taste. Spread sweet potato puree on the cooled crust.
  • Peel and slice onions into rings. In a skillet over medium-high heat, melt the coconut oil and add the onions and salt. Cook, stirring occasionally until the onions are caramelized, about 20 minutes. While the onions are cooking, tear the mushrooms into large pieces. Add them to the skillet, stir to coat, and let them sit in the pan undisturbed for at least 5 minutes until they begin to develop some colour on the bottom. Turn the mushrooms over and let them cook until both sides are nicely golden. Remove from heat and immediately add the balsamic vinegar, black pepper, and fresh thyme. Season to taste.
  • Place the mushrooms and onion mixture on top of the sweet potato puree. Instead of spreading it out, I like to pile it up for a more ceremonial effect — I'll leave that part up to you! Drizzle the top with a little olive oil, garnish with a couple sprigs of fresh thyme, and serve hot.


Serves 4-6