For crust, beat butter until smooth. Add icing sugar and lemon zest and cream together. Stir in egg yolks, one at a time, stirring well after each addition. Sift pastry flour and salt into butter mixture and stir just until dough comes together (turn out onto a board and bring together with your hands, if needed). Shape dough into a disc and chill for at least 1 hour.
On a lightly floured surface, roll out pastry to ¼ inch thick. Sprinkle a 9-inch fluted tart pan (with 1 ½ inch sides) with a removable bottom with a little flour and line with pastry. Trim edges and press pastry up, so it stands about ¼ inch higher than the sides of the pan. Dock pastry with a fork and chill 20 minutes.
Preheat oven to 350 °F. Bake pastry shell for 18 to 20 minutes, until edges are a light golden brown and center appears dry. Allow to cool.
For filling, whisk together 1/3 cup raspberry purée, lemon juice, eggs, yolks, and sugar. Whisk in butter and add lemon zest. Place bowl over a pot of simmering water and whisk steadily, but gently, until curd becomes thick and pale and creamy, about 10-15 minutes. Remove from heat and cool to room temperature. Stir in remaining 1/3 cup raspberry purée and pour into cooled pastry shell.
For fruit, slice peaches or nectarines and apricots and toss in lemon juice to prevent discolouration. Slice strawberries in half. Arrange fruit on chilled tart up to 2 hours before serving and chill until ready to serve.
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