Place a baking sheet in the oven and preheat to to 200C/390F (180C/355F fan). This is important as it helps ensure the pastry bases cook through properly - no soggy bottoms!
In a food processor, add the butter and flour and blitz until the mixture has a breadcrumb consistency.
Add the egg and blitz again, if it doesn't start to come together add 1-2 tbsp of water and blitz again.
Work the dough into a ball then cut into four and roll those into balls.
Grease four tartlet tins with butter, oil spray or cake release spray.
On a lightly floured work surface, roll out each dough ball to a couple of centimetres than the tartlet tins - just wide enough to line the holes of your tart tins. Press into the tins.
Cover with cling film and pop in the fridge.
For the filling
Heat the olive oil over a medium heat and add the sliced onions and a pinch of salt. Fry for 10-12 minutes until starting to soften then set aside to cool.
Meanwhile, in a bowl, add the cream, egg yolks and a pinch of salt and pepper and whisk.
Add the goat's cheese and the de-stalked rosemary and stir.
Add the cooled onions and mix again.
In a food processor blitz the cranberries and pistachios until they have the consistency of crumble.
Putting it all together
Take the cases out of the fridge. They should feel very firm.
Sprinkle the cranberry and pistachio mix evenly between the cases.
Pour in the cheese and cream mixture evenly between the cases.
Arrange the sliced pear on top, season with salt and pepper and drizzle with olive oil.
Bake for 20-25 minutes or until golden brown and risen. Allow to cool for a few minutes, then once cool enough to handle, carefully release from the tin.
Top each tart with a sprig of fresh rosemary.
Enjoy hot or cold, but always with a cool glass of Robinsons Pressed Pear & Elderflower Fruit Cordial!