Start by preparing the tart crust. You could optionally use store-bought crust as well.

Pulse the cold butter pieces with the flour in a food processor, or optionally, use your hands to combine, working quickly to avoid softening the butter.

Turn out the flour mixture on a work surface and add the ice-cold water and quickly mix it with the processed flour.

Bring it together like a dough, and let it chill in the fridge for 10 minutes. Once chilled, gently roll it out between two sheets of cling film, and transfer the rolled out dough into a tart or pie baking pan.

Press the dough into the pan, and let it chill in the freezer for 20 minutes. You can prepare the onion jam in the meantime.

For the onion jam:

In a hot pan, add the olive oil and turn the heat to low-medium

Add the onions, and let them cook.

While the onion is cooking, roast the garlic cloves in the oven, for 10 minutes on 180C.

Make sure you stir the onions at regular intervals and continue cooking for 20 minutes until the onions are softened. Add in the roasted garlic, balsamic vinegar, a pinch of salt and 1/2 a cup of water.

Lower the heat and continue to cook for another 20-30 minutes on low heat until the onions are dark brown and very soft. The onion jam is done. Keep aside.

When you are ready to prepare the tart, take the tart pan with the crust out of the freezer and bake it for 10 minutes at 150 C.

Now prepare the filling. Whisk together the goats cheese, grated Parmigiano-Reggiano, eggs, thyme leaves and a pinch of salt. Pour this into the baked tart crust. Top with the onion jam.

Bake for 10 minutes at 150C.