01 -
In a big pan, warm up oil over medium heat. Toss in the onions and stir every now and then till they're golden and tender, which takes about 35 minutes. Add a pinch of salt and let them cool down.
02 -
While the onions cool, grab a small bowl and add the goat cheese. Sprinkle the black pepper over it, then mix until it's creamy and easy to spread.
03 -
Set your oven to 375°F. Cover a baking tray with parchment paper.
04 -
Unroll the puff pastry onto your lined tray. Spread the cheese across the top, leaving a little border around the edges. Scatter the onions evenly and finish with a dusting of thyme.
05 -
Pop the tart in the oven and bake until the crust is crisp and golden, about 25 to 30 minutes.
06 -
Let it rest for 15 minutes. Slice into rectangles around 2x3 inches each. Serve it warm or once it reaches room temperature.