Onion Tart Recipe

Measure and prep all ingredients.

Prepare the rough puff pastry. In a large bowl, add the all-purpose flour, salt and sugar. Mix until combined. Add the cold butter and coat the butter with the flour. 

Add the ice cold water and mix with a fork to hydrate the flour. 

Work the dough with your hands quickly so the butter does not melt. You want to make sure you still have some large chunks of butter mixed in.

Once a shaggy dough has formed, turn the dough out onto a lightly floured countertop. Bring the dough together into a disc and flatten slightly. You should still see nice chunks of butter throughout the dough. Wrap the dough in plastic wrap and place it in the refrigerator for 2 hours. 

After the 2 hours, take the dough out of the refrigerator and onto a lightly floured surface. Roll the dough out to a 13x7-inch rectangle. 

Fold the dough into thirds, similar to folding a letter. 

Turn clockwise and roll the dough back out to a 13x7-inch rectangle and fold it into a letter again. Repeat this process four more times for a total of six times. Cover the folded dough with plastic wrap and refrigerate for 30 minutes to an hour before use. (See notes 2.) 

When ready to use, roll the dough out in a 17x10-inch rectangle. Place on a baking sheet lined with parchment paper. Score around the tart, one inch away from the edge to create a border. Make sure you lightly score and do not cut off the pastry's edge. Place the sheet pan in the refrigerator until ready to use.

Prepare the onion filling. In a large pan over medium heat, melt the butter and olive oil. Add the sliced onions, leeks, sugar, allspice, salt and pepper. Sauté until the onions are caramelized.

Once the onions have carmelized, add the garlic for a couple of minutes and remove from heat. Taste and if needed, adjust seasoning with salt and pepper. 

Assemble the onion tart. Preheat the oven to 400°F. In a medium bowl, add the ricotta and the egg. Mix until combined. 

Add the ricotta filling to the middle of the tart and spread evenly within the border line of the tart.

Next, add the onion mixture over the ricotta mixture and spread it evenly. 

Pull the leaves from the thyme sprigs and add them to the shredded Gruyere. Mix together. 

Finally, sprinkle the Gruyere cheese mixture evenly over the tart. 

Bake in the oven for 20-25 minutes. The tart dough should be golden brown. Slice, serve and enjoy!