This caramelized onion tart recipe is a savory tart made with juicy caramelized sweet onions, crumbled feta, sweet fig jam, and flaky puff pastry.
Preheat the oven to 400 F. In a large skillet cook onion over medium heat with some olive oil until softened and add sugar and vinegar. Simmer until sugar is melted, bubbly, syrupy, and a dark golden brown.
Score the crust about 2 inch from the edges of the puff pastry rectangle with the tip of a sharp knife and poke the inside several times with the tines of a fork.
Spread most of the fig jam across the inside of the puff pastry and reserve some for later.
Arrange cooked red onion and top with feta cheese and cubed butter.
Fold in the edges and brush with egg wash. Bake for 20-25 minutes until golden brown. Brush with the remaining fig jam (for best results warm it up in the microwave until loose texture).
Allow to cool for a few minutes, slice, and serve this Caramelized Onion Tart warm!