Sweet Potato Onion Upside Down Gratin

Sweet and savory. This baked gratin of sweet potatoes, goat cheese, caramelized onions with a touch of maple syrup is served upside down and sprinkled with buttery, crunchy breadcrumbs.

Sweet Potato Onion Upside Down Gratin 

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  • 7 cup cherry or grape tomatoes
  • 2 tablespoon olive oil, plus extra for drizzling
  • 1 pound small sweet potatoes, about 2‑inches diameter at widest
  • 1 large onion, thinly sliced
  • 2 tablespoon maple syrup
  • 1 tablespoon thyme leaves
  • 5 ounce aged (hard) goat’s cheese, sliced
  • 2 tablespoon unsalted butter
  • 1 cup panko breadcrumbs


Preheat the oven to 250°F. Halve the tomatoes and place them cut-side up on a baking-sheet. Drizzle over some olive oil and sprinkle with salt and pepper. Place in the oven to dry for 1 hour & 15 minutes to dry. Too much juice will make the gratin difficult to unmold.

Meanwhile, cook the whole potatoes, with their peels in boiling salted water for 15 minutes. They should get a bit soft, but not thoroughly cooked. Drain and let cool. Trim a bit of the pointy ends off each potato, then cut into 3/4‑inch thick rounds.

In a medium sauté pan cook the onion over medium heat with 2 tablespoons oil and a big pinch of salt , stirring often, until lightly caramelized to golden brown. About 18 minutes. Once you’ve prepared all the vegetables, brush a 9″ cake pan with a bit of oil, then line the bottom with a circle of parchment paper.

Pour the maple syrup into the cake tin and tilt it to spread evenly over the bottom. Scatter half of the thyme leaves on top of the syrup. Lay the potato slices close together, cut-sides down, on the bottom of the tin. Gently press the onion and tomatoes into the gaps and sprinkle generously with salt and pepper. Spread the slices of goat’s cheese evenly on top. At this stage you can chill the gratin for up to 24 hours.

When ready to bake. Preheat the oven to 400 degrees F. Bake the gratin for 25 minutes, then reduce the temperature to 350 degrees F and continue baking for another 15 minutes, or until the potatoes are thoroughly cooked.

While the gratin bakes prepare the breadcrumbs. In a small skillet set over medium heat, melt the butter. Add the panko and toast, stirring constantly, for about 3 minutes until golden brown and crisp. Remove from the heat and stir in the remaining thyme leaves, and a pinch of salt. Set aside.

When the gratin is finished cooking remove it from the oven and let rest for two minutes and no more. Hold an inverted plate firmly on top of the pan and carefully but briskly turn them over together, then carefully lift off the pan.

Sprinkle each individual serving with toasted bread crumbs. Serve warm.