Butternut, maple & pecan lattice pie

Name: Butternut, maple & pecan lattice pie
Prep time: 20 min
Cook time: 1 h 10 min
Total time: 1 h 30 min
Cuisine: American
Ingredients: 700g chunk butternut squash or pumpkin; 1 tbsp vegetable or sunflower oil; 175g light muscovado sugar; 250g tub mascarpone; ½ tsp freshly grated nutmeg; 1 heaped tsp ground cinnamon; 1 heaped tsp ground ginger; 2 eggs; 3 tbsp maple syrup , plus more to serve; 1 tsp vanilla extract; 2 x 375g packs chilled dessert pastry; plain flour , for rolling; milk , for brushing; handful pecan halves, very roughly chopped; icing sugar and whipped cream, to serve