2375gm butter puff pastry sheets (see note)300 gmricotta1egg1lemon, finely grated rind and juice only2 tbspthyme leaves½small garlic clove, finely grated¼small Spanish onion, thinly sliced60 ml(¼ cup) extra-virgin olive oil, plus extra for drizzling4thin slices round pancetta1 tspaged balsamic vinegar 250 gmsmall tomatoes, such as cherry or yellow grape, halvedTo serve:small basil leaves
Preheat oven to 200C. Cut four 12cm-diameter rounds from pastry and place on a baking paper-lined oven tray. Score inside edges to form a 1cm border, prick within border with a fork and set aside in refrigerator.
Combine ricotta, egg, lemon rind, thyme and garlic in a bowl, season to taste and mix until smooth. Divide mixture among pastry bases, spreading evenly within border. Scatter over onion, drizzle with a little oil and bake until puffed and golden (15-20 minutes).
Meanwhile, place pancetta on a baking paper-lined oven tray and bake until just crisp (2-3 minutes), coarsely chop and set aside.
Combine lemon juice, vinegar and olive oil in a small bowl, season to taste and mix to combine. Add tomatoes, toss to coat, spoon into tartlets and serve immediately scattered with basil leaves and pancetta.
NoteCarême puff pastry comes in pre-rolled 375gm sheets. If unavailable, substitute with another good-quality butter puff pastry.