Grease a 10-inch (25cm) tart pan with a removeable base.

Place flour, powdered sugar, ground almonds and butter in the bowl of a food processor; blitz until the butter is coarsely chopped. Add egg yolks and only enough water to bring the dough together until it resembles wet sand. Tip the mixture onto a flour counter and press the dough together to form a disc. Using a well-floured rolling pin, roll the pastry, turning it to ensure it’s evenly rolled and not sticking to the counter. Roll it to fit into the base and side of the tart pan, bringing the pastry a little higher up the side of the pan to allow for shrinkage when it’s blind-baked. Cover with plastic wrap and chill for 1 hour.

Preheat the oven to 375°F (190°C). Place a piece of parchment paper in the tart pan covering the pastry. Add pastry weight, rice or dried legumes onto the parchment. Bake the pastry for 15 minutes. Carefully remove the paper and pastry weights. Further bake the pastry for 10 to 15 minutes until golden brown. Let the pastry cool. Reduce the oven temperature to 350° (180°).

In a large bowl; whisk together all the filling ingredients. Let stand for 10 minutes. Whisk again then pour into the pastry shell. Bake for 25 minutes or until the filling is only just set in the middle. Let cool. Carefully cover the tart. Chill for 8 hours or overnight.

Combine the sugar and water in a large frying pan over medium-high heat. Stir until the sugar is dissolved. Add the lemon slices in a single layer. Cook, uncovered for 10 minutes or until slightly candied and translucent. Remove to an oiled plate to cool. Once cool, arrange over the top of the tart. Dust with powdered sugar if desired. Cut into 8 pieces. Serves 8.