Red Onion, Thyme and Parmigiano Reggiano Tart

This red onion, thyme and Parmigiano Reggiano tart blends a handful of high-quality ingredients. The star is 24-month aged Parmigiano Reggiano, which adds depth and complexity to every bite. Caramelized red onions and the sharp, nutty cheese make a sweet-salty contrast, with crisp, flaky pastry for texture. Let the tart cool slightly after baking, slice it and serve with a fresh green salad as a meal or appetizer.

Ingredients for 4 people

• 50g unsalted butter
• 1kg red onions, peeled and sliced lengthways
• Salt and freshly ground pepper to taste
• 1 pack puff pastry, ready rolled, preferably all butter (pack size varies from 320g to 375g)
• Oil and flour for the baking sheet
• 1 egg, beaten with a pinch of salt
• 1.5 g fresh thyme, leaves only, picked from approx. 6–8 sprigs (1 tbsp)
• 100g Parmigiano Reggiano

How to make Red Onion, Thyme and Parmigiano Reggiano Tart

1. Preheat the oven to 180°C (fan).
2. Melt the butter in a heavy pan and sauté the onions over low to medium heat, stirring frequently, until completely softened, 30 to 40 minutes. Season along the way and check the seasoning at the end: the sweetness of the onions needs enough salt to balance it.
3. While the onions cook, prepare the pastry base. Oil an approx. 35 cm x 25 cm baking dish and dust with flour. Unroll the pastry and place it on the baking sheet. With a sharp knife, score a 1–2 cm border around the edge and prick the pastry within the border with a fork. Brush the border with egg. Bake at 180°C (fan) for 20 minutes, until golden and puffed up.
4. Increase the oven to 200°C (fan).
5. Spoon the cooked onions onto the pastry, within the border. The weight of the onions will collapse the pastry, but it will be cooked properly. Cover the onions with the Parmigiano Reggiano and sprinkle the thyme leaves on top. Give the border another egg wash and return to the oven for 10 minutes, until lightly browned on top.
6. Serve after the tart has been out of the oven for 15–30 minutes, to cool a little. Cut into four or six pieces and serve with a simple dressed green salad.

Tips

Pre-cook the pastry

The recipe has just a few ingredients, but technique is important. Although not commonly instructed, it is best to pre-cook the puff pastry so it is fully cooked and you are not left with a layer of uncooked pastry, especially away from the edges.