Ingredients

Step by step

1. For the pastry, finely grind the sugar and walnuts in a food processor. Add the flour and butter and whiz to a fine crumb texture. Add the yolk plus 2 tablespoons of cold water and pulse until it comes together in clumps, adding a little extra water if needed. Bring together in a ball, flatten into a disc and wrap in clingfilm; chill for 30 minutes.
2. Meanwhile, preheat the oven to 200°C, fan 180°C, gas 6. Wrap the pumpkin or squash in foil, pop on a baking tray and bake for 50 minutes until very tender. Leave the pumpkin to cool for 10 minutes, then put into a food processor or blender with the eggs and whiz until smooth.
3. Set aside 75g pastry for the decorations. Divide the rest of the pastry into 8 and roll out one piece at a time to a disc about 15cm in diameter. Use to line 8 x 10cm nonstick mini pie or tartlet tins that are 2.5cm deep, making sure the pastry is slightly proud of the rims of the tins. Prick the base of each tart with a fork then press the back of the fork all around the edges of each one to make a pattern. Put the tins on a baking tray and chill the pastry cases for 30 minutes.
   Tip

   Want to make one large tart? Use a 23cm-diameter fluted tin that's 3cm deep and blind-bake the pastry case for 20 minutes, then add the filling; bake for 40-45 minutes until set. If you're short of time, use 500g ready-made shortcrust pastry, but line the tart case with baking paper and fill with baking beans before blind-baking, to prevent the pastry shrinking during cooking.
4. Roll out the reserved pastry and use a star or leaf-shaped cutter to stamp out decorations for the edges of the tart, put them on a plate and chill those, too.
5. Bake the tartlet cases for 10 minutes on the baking tray. In a small bowl, lightly beat the egg with ½ teaspoon of cold water and brush over the inside of the pastry cases and the pastry rims. Bake for a further 5 minutes until the pastry is crisp and golden. Reduce the oven temperature to 180°C, fan 160°C, gas 4.
6. Whisk the soft butter, condensed milk and brown sugar together in a bowl, then whisk in the pumpkin mixture and stir in the orange zest. The filling will look slightly curdled, but becomes velvety smooth during cooking. Brush the pastry leaves with beaten egg.
7. Divide the filling between the pastry cases (they will be about two-thirds full); arrange a few pastry decorations around the rims. Bake the tarts at the lower oven temperature for 20-25 minutes, or until the filling is set.
8. Allow the tarts to cool for 10 minutes. For the Chantilly, dice the Gorgonzola and whisk with the icing sugar and 2 tablespoons of the cream until smooth, using an electric handheld whisk, then whisk in the rest of the cream until the mixture holds its shape.
9. Ease the tartlets out of the tins, scatter with a little brown sugar and serve with the blue cheese Chantilly.