Ingredients

• 6 firm ripe pearsConference or Comice, giving only at the neck; a soft pear disintegrates
• 120 g caster sugar
• 70 g unsalted buttercubed
• 1 tsp lemon juice
• 320 g all-butter puff pastryall-butter, ready-rolled
• 250 g mascarponefull-fat, cold
• 1 tbsp icing sugar
• 1 tsp vanilla bean paste
• 1/4 tsp flaky sea salt

Method

1. 01

   Prepare the pears

   Peel the pears, halve them lengthways and remove the cores with a teaspoon, scooping a neat hollow rather than cutting a wedge. Trim out the fibrous string running from core to stalk. Keep them in a bowl of water with a squeeze of lemon while you work so they do not brown, then pat completely dry before they meet the caramel. Water and hot caramel is a bad combination.

2. 02

   Make a dry caramel

   Scatter the caster sugar in an even layer across a dry 24 cm ovenproof frying pan and set over medium heat. Leave it alone until the edges begin to melt and go clear, about 3 minutes, then swirl the pan, never stir with a spoon, and keep swirling as the liquid spreads inwards. Cook for 6-9 minutes total until it is a deep amber, the colour of an old penny, with the first wisp of smoke coming off it. Going this dark feels risky and it is exactly right: pale caramel under six sweet pears tastes of nothing.

   120 g caster sugar

3. 03

   Finish the caramel

   Take the pan off the heat and drop in the cubed butter a few pieces at a time, swirling hard. It will bubble up furiously. Once it is emulsified and glossy, add the lemon juice and a pinch of flaky salt. The lemon does two jobs: it cuts the sweetness and it keeps the caramel from crystallising as it cools.

   70 g unsalted butter · 1 tsp lemon juice

   If the caramel seizesBack on low heat and swirl until it comes together. Butter off the heat, a few cubes at a time.

4. 04

   Arrange the pears

   Off the heat, pack the pear halves into the pan cut-side up, rounded backs down, in a tight circle with their narrow ends pointing to the centre, filling any gaps with trimmed pieces. Cut-side up now means cut-side up in the finished tart once it is inverted, which is what gives you those glossy domed halves. Pack them tighter than looks sensible. They shrink by a third.

5. 05

   Pre-cook the pears

   Return the pan to medium heat and cook for 8-10 minutes, basting the pears with the caramel by tilting the pan and spooning it over every couple of minutes. The caramel should be bubbling steadily but not violently. The pears will release liquid at first and then start to take it back; they are ready when the caramel has thickened again and the pears are tinged gold underneath. This step is what stops the finished tart being watery.

6. 06

   Top with pastry

   Heat the oven to 200C fan / 220C conventional. Unroll the cold pastry and cut a circle 2 cm wider than the pan. Lay it over the pears and tuck the overhang down inside the pan edge with the back of a spoon, working quickly. The pan is hot and warm pastry does not puff. Prick the surface five or six times with a knife tip to let steam out.

   Shop-bought pastry is fineReady-rolled all-butter outperforms most homemade rough puff. Spend the effort on the caramel.

7. 07

   Bake

   Bake for 25-30 minutes until the pastry is deeply golden brown, well risen and crisp all the way to the centre. Lift an edge with a palette knife and look underneath; pale pastry will go soggy the moment you invert it. If it is browning too fast, drop to 180C fan and give it the full 30 minutes.

8. 08

   Rest and invert

   Rest the pan for exactly 5 minutes. Long enough for the caramel to thicken so it does not run everywhere, short enough that it has not set and glued the pears to the pan. Run a knife around the edge. Place a serving plate larger than the pan upside down over the top, hold it firmly with a cloth over both hands, and flip in one confident movement. Lift the pan away. If a pear sticks, lift it off with a palette knife and put it back in place, nobody will know.

9. 09

   Make the vanilla mascarpone

   Beat the cold mascarpone with the icing sugar and vanilla bean paste for about 30 seconds, just until smooth and spoonable. Stop there: mascarpone splits into grains if you whip it hard. Serve the tart warm, in wedges, with a cold spoonful of the mascarpone on each. The temperature contrast against the hot caramel is the point of the dish.

   250 g mascarpone · 1 tbsp icing sugar · 1 tsp vanilla bean paste

   Poach the pears firstFive minutes in vanilla syrup before they meet the caramel, if you have the time.