Potato, Onion, Gruyere Tart

Bought too many fingerlings,
What should I do with all these things?

Slice ’em up into a tart,
That sounds like a decent start.

Add sweet onions, caramelize,
Gruyere will make this tart a prize.

Bake it ’til there’s golden crust,
Rosemary sprinkle is a must.

Slice it up and serve it warm,
Careful ‘cuz your guests will swarm. 🙂

My friend, Sara, from OneTribeGourmet, inspired me to make this tart when she posted a pissaladiere just like this but with different ingredients. I made her recipe and it was so good I thought I would make one of my own. Any potatoes will do, although I think Yukon Gold would be best. I just happened to have fingerlings on hand.

Potato, Onion, Gruyere Tart
8 Fingerlings or 4 Yukon Gold (medium-sized) potatoes, sliced thinly
1 sweet Vidalia onion (medium-sized), sliced thinly
2 tsp. fresh rosemary (and some extra for garnish)
1/3 cup extra virgin olive oil
2 tsp. kosher salt
1/2 tsp. coarse pepper
1 sheet frozen puff pastry, thawed
1 cup Gruyere cheese, grated
1 egg yolk + 1 tsp. water, lightly beaten

Preheat oven to 400 degrees. Add potatoes, onions, rosemary, salt, and pepper to a saute pan coated with olive oil. Cook on medium for about 10 minutes or until the potatoes are just tender. Set aside.

Roll out the puff pastry to the length and width of the tart pan and transfer it on top of the pan. Fill the pan’s wedges in with the dough. With a fork, prick the dough all over the bottom and sides. Brush the pastry with the egg wash.

Fill the tart pan with the potato and onion mixture and top it with the Gruyere. Place it into the oven to bake for 20-25 minutes or until the edges are golden brown. Garnish with chopped rosemary.  Slice and serve warm.