To prepare the crust, mix together the dry ingredients in a large bowl. Grate the frozen butter over the bowl on the largest hole setting, stopping every couple minutes to stir in the grated butter bits so that they don’t form one giant butter shard clump. Add the water in small increments, stirring, until all the water is added. Knead the dough for about 30 seconds to help disperse the moisture, then grab a handful of the mixture and squeeze. If it generally sticks together when you let go, it is fine. If it completely crumbles apart, it needs another tablespoon or two of water. Once the dough holds its shape, divide it into two balls, cover each with plastic wrap and place them the refrigerator.

For the filling, whisk together the golden syrup, flour, sugar, cinnamon, cloves, and salt in a medium bowl. Add the fruit and toss to coat. Set aside. Roll out one of the dough balls on a clean working surface until it is about 1/8 inch thick. Transfer it to an 8-inch pie dish and press it into the pan, leaving the sides overhanging. 

Now roll out the second dough ball into a circle. This will make the lattice top. Cut the rectangle into 30 long strips using a pizza or pastry wheel. Braid three strips together, and repeat until you have 10 separate braids. Pour the filling into the pie crust shell. Weave a lattice pattern using your braids, with five going vertically and five going horizontally. Trim the edges of excess crust overhand and place the pie in the oven. Bake until golden on top and filling is soften, about 1 hour. Remove and allow to cool for 30 minutes before slicing and serving alongside the white chocolate mascarpone.