Emmi Gruyère and Caramelized Onion Tart with Apples and Sage in a Buckwheat Crust

By Caroline Schiff, Pastry Chef, Brooklyn, NY

Want to try cheese and sweets together? This is the perfect recipe to add to your collection of fan favorites.
One 8" Tart
Prep Time
Cook Time
Total Time


  • For Crust:
  • ¼ cup plus 2 tablespoons whole wheat flour
  • ¼ cup buckwheat flour
  • ¼ teaspoon kosher salt
  • 1 ½ teaspoon potato starch
  • 4 tablespoons butter, chilled and cut into little cubes
  • 3 to 4 tablespoons ice cold water
  • AP flour for work surface
  • For Filling:
  • 2 tablespoons olive oil
  • 2 yellow onions, sliced thin
  • 1 teaspoon kosher salt
  • ¼- ½ teaspoon freshly cracked black pepper
  • 1 tablespoon butter
  • ¼ cup dry white wine
  • 1 cup Emmi Le Gruyère AOP, grated
  • 1 medium apple, cut in half, cored and sliced 1/8” thick
  • Approximately 4-6 large, fresh sage leaves, finely chopped, plus some little ones to garnish
  • 1 large egg
  • ¼ cup heavy cream


  1. For Crust: In a mixing bowl combine all the dry ingredients with the butter. Cut the butter into the flours using a pastry cutter or pinching it between your fingers until the butter is pea sized and the mixture has a crumbly, dry appearance.
  2. Add the ice water a couple of tablespoons at a time, gently bringing the dough together with your hands. The dough should just hold together when a handful is squeezed together. Don’t add too much water or it will become over-hydrated.
  3. Form the dough into a disc and wrap in plastic. Chill at least two hours or overnight before rolling.
  4. On a floured surface roll out the chilled* dough into a circle 12 inches in diameter, rotating as you go for an even thickness. Draping over your rolling pin, gently transfer the dough to an 8” tart pan with removeable bottom, pressing it in and trimming off the extra, or leaving it rough for a rustic look. If you have a few cracks, don’t worry about it. Just gently patch them up with some of the trim. *Buckwheat doesn’t have any gluten so it’s quite delicate. Rolling out this dough chilled makes it a little easier to work with.
  5. Chill the formed crust for 30 minutes. Meanwhile, preheat the oven to 350. After 30 minutes, line the tart with a piece of parchment paper and fill with pie weights or dry beans to blind bake.
  6. Place the crust on a sheet pan so it’s easy to transfer to the oven and bake for 30 minutes.
  7. When done allow the crust to fully cool before removing the pie weights or beans (you can save them for another pie!). While the tart shell bakes and cools you can start the filling.
  8. For Filling: First, caramelize the onions. In a large skillet over medium flame, heat the oil until it shimmers. Add the sliced onion, salt and pepper, and cook over medium heat until soft and caramelized, about 30-40 minutes, stirring frequently. Reduce the heat if you notice any scorching.
  9. When caramel in color, add the wine and then butter, allowing it to melt through and evaporate, cooking another 2 minutes. Take off the heat to cool and set aside.
  10. When the onions have cooled to room temperature, fold in the egg, cream, chopped sage and ¾ cup of the grated cheese.
  11. Transfer the filling to the par baked crust and spread into an even layer.
  12. Fan out the apple slices in a circle on top of the filling, shingling them slightly so they fill the surface of the tart in a spiral. Press them into the filling slightly, and top with the remaining ¼ cup of cheese. Lower the oven temperature to 325 degrees.
  13. Transfer the tart to the oven on a sheet pan and bake until the apples have softened, and the filling is bubbling, about 35 minutes. Transfer to the broiler and cook another two minutes or until the Gruyere is crusty, golden, bubbly and delicious. This part goes fast, so keep an eye on it!
  14. Remove from the oven and leave at room temperature until it’s cool enough to gently unmold from the tart pan, pressing from the bottom to release the edges. Garnish with extra sage leaves if desired. Eat while still slightly warm or re-heat for 10 minutes in a 300-degree oven on a sheet tray. Enjoy by itself or with a side salad; a glass of wine won’t hurt either.