A DEBATE with Yotam Ottolenghi and Helen Goh on the merits of any particular cake, biscuit or pudding, spirals into serious, labyrinthine assessments of silkiness and nuttiness, crumb size and snap.

Israeli-British chef Yotam, 48, co-owner of the Ottolenghi delis and restaurants, and pastry chef and psychologist Helen, 51, have spent the last three years concocting sugary treats to include in their new book of desserts, Sweet. It's his sixth book and her first.

In it there are mini berry frangipanes, decadent cream-frosted puds and cookies galore - all of which have been put through the pair's ruthless, multi-stage recipe-testing regime.

Here is one of their recipes to try at home.

Mont Blanc Tarts

Ingredients:

(Makes 8)

For the pastry:

200g plain flour

120g unsalted butter, fridge-cold, cut into 1cm dice

30g caster sugar

1/4tsp salt

1/2tsp white wine vinegar

3tbsp ice-cold water

For the filling:

60g dark cooking chocolate (70 per cent cocoa solids)

320g sweetened chestnut spread (we use Clement Faugier; whichever brand you use, just make sure that it is not the unsweetened variety)

For the candied pecans:

1tbsp maple syrup

1tbsp liquid glucose

1tbsp caster sugar

120g pecan halves

1/8tsp flaky sea salt

For the vanilla whipped cream:

300ml double cream

1tbsp icing sugar

1tsp vanilla extract

1/2tsp brandy

Method:

1. For the pastry, place the flour, butter, sugar and salt in the bowl of a food

processor. Blitz a few times, until it is the consistency of fine breadcrumbs, then add the vinegar and water. Continue to work for a few seconds, then transfer to your work surface. Shape into a ball and flatten into a disc, wrap in cling film and set aside in the fridge for at least one hour (or up to three days).

2. Preheat the oven to 200°C/Gas Mark 6.

3. Allow the dough to rest at room temperature for 30 minutes (if it has been in the fridge for more than a few hours) and place on a lightly floured work surface. Roll out the dough to about 3mm thick and cut out eight circles, 14cm wide. Re-roll the dough, if necessary, to get eight circles. Transfer one circle at a time to the 8-9cm wide and 2-3cm deep fluted tins and gently press the pastry into the corners of the tart tin. You want it to fit snugly and for there to be a decent amount of pastry hanging over the edge of the tart case, as the pastry can shrink a little when baked. Place in the fridge for 30 minutes to rest.

4. Line the pastry bases with baking parchment or paper liners and fill with baking beans. Bake for 18 minutes, until the pastry is golden brown at the edges. Remove the beans and paper and cook for another eight minutes, or until the base is golden brown. Remove from the oven and set aside to cool completely in the tray. Once cool, trim the pastry and set aside until ready to fill.

5. Increase the oven temperature to 210°C/Gas Mark 6. Line a baking tray (with a lipped edge) with baking parchment and set aside.

6. To make the candied pecans, put the maple syrup, glucose and sugar into

a small saucepan and place over a low heat. Stir gently until the sugar has melted, then add the pecans and salt. Stir so the nuts are coated in syrup, then tip the nuts on to the lined baking tray. Place in the oven for about eight minutes, or until the syrup is bubbling around the nuts. Remove the tray from the oven and set aside until completely cooled. When the nuts are cooled, the glaze should be completely crisp; if not, return them to the oven for a few more minutes. Once cooled, break or roughly chop the nuts into 0.5cm pieces and set aside until ready to use.

7. Make the filling when you are ready to assemble. Place the chocolate in a heatproof bowl over a pan of simmering water, making sure the base of the bowl is not touching the water. Stir occasionally until melted, then use a pastry brush to line the inside of each case with the chocolate. Set aside for about 30 minutes, to set, then fill with enough chestnut spread so it rises about halfway up the sides of the tart cases.

8. For the vanilla whipped cream, pour the cream into the bowl of an electric mixer with the whisk attachment in place. Add the icing sugar, vanilla extract and brandy and whisk on a high speed for one minute, or until medium-soft peaks form.

9. Divide the whipped cream between the tarts, so it is slightly domed on top of the chestnut spread. Sprinkle the candied pecans generously on top. Serve.

n Sweet by Yotam Ottolenghi and Helen Goh is published by Ebury Press, priced £27. Photography by Peden + Munk.