These make for a superb lunch; they're also the perfect starter for a dinner party. You can make the caramelised onions in the morning, or even the night before, and keep them covered until required. Take care when cooking the tartlets ~ I have made the mistake many a time of serving a beautiful, well-risen tart only to discover upon eating it that the base isn't cooked properly! Check by using a palette knife or similar to gently life the tartlets and make sure the bases are not soggy or soft. If they are, reduce the oven temperature to 160˚C (fan) 180˚C and return to the oven for further cooking.
This recipe is essentially 2 recipes combined; 1 for the tartlets but also for an onion jam I have been making for years. It is a thick, sweet and very yummy onion jam and is used for the base of these tartlets, but you can also serve it with a good vintage cheddar as part of a cheeseboard, or spread on a grilled cheese sourdough sandwich.
4 large onions, peeled + finely sliced
2 tbsp olive oil
Sea salt flakes
3 tbsp balsamic vinegar (plus a bit extra if required)
1 1/2 tbsp soft brown sugar
1 large sheet good quality puff pastry
1 free-range egg yolk, mixed with a splash of milk
4 heaped tbsp caramelised onion jam (see below)
175g good-quality goat's cheese, cut into 1.5cm thick rounds
3-4 thyme spring, leaves picked, plus extra sprigs to garnish
Sea salt + freshly ground black pepper
250ml balsamic vinegar (use the best you can afford)
3 tbsp brown sugar
TO MAKE THE ONION JAM
Place onions into a large, deep heavy-bottomed saucepan and drizzle with olive oil. Using a wooden spoon, stir the onions to coat thoroughly with the oil, then season with a good pinch of salt.
Cook over medium-high heat for about 15 minutes or until softened. Turn the heat down to low and continue cooking for a further 30 minutes, stirring frequently to scrape any sticky bits from the bottom of the pan.
Add the vinegar and sugar and stir to coat well. Continue to cook over low heat for another 30-45 minutes, again scraping all the sticky bits from the bottom of the pan. Add a splash more vinegar if the jam becomes too sticky – the consistency should be that of a thick, luscious marmalade. Set aside to cool. This will make 1.5 cups or 375ml of jam. Store excess in a sterilised jar and keep in the fridge for up to 1 week.
TO MAKE THE TARTLETS
Preheat the oven to 200˚C (fan-forced), 220˚C
Using a 12cm round pastry cutter or a small bowl as a template, cut four rounds of pastry and place on a large non-stick or lined baking sheet. Score a 2cm border around the edges of the rounds, being careful not to cut all the way through. Avoiding the border, prick the bases all over with a fork. Brush the borders with the egg wash, taking care not to let the egg run down the sides or the pastry will rise unevenly.
Again, avoiding the border, divide the caramelised onion jam among the bases, spreading it out evenly. Place a round of goat's cheese on top, then scatter with the thyme leaves and season with pepper.
Bake for 20 minutes or until the puff pastry borders are golden and risen and the bases of the tartlets are cooked.
Mean while, place the balsamic vinegar in a small saucepan and bring to the boil, then reduce the heat and simmer until reduced by half. Add the brown sugar and simmer until the mixture becomes syrupy – it should coat the back of a spoon when it's ready. Set aside to cook and thicken.
Serve the tartlets drizzled with the balsamic syrup and scattered with thyme sprigs.