In a large bowl whisk together the flour, sugar and baking powder, create a well in the middle, add the slightly beaten egg, yolk and the room temperature butter cut into pieces. Mix together, at this point turn mixture onto a slightly floured surface and work the mixture to form a soft dough (if dough is very dry then add an extra tablespoon of soft butter).
Wrap the dough in plastic and refrigerate for 30 minutes. Remove the dough from the fridge and knead the dough a couple of times to soften it up again on a lightly floured surface. Roll out to 1/8" thickness.
Pre-heat oven to 350F (180C), grease and flour an 8 or 9 inch- (20 - 22 cm) pie dish.
Transfer to the prepared pie plate, I used a 8" pie dish (20 cm). Trim the dish of any extra dough. Prick the dough with the tongs of a fork, then spread the pastry shell with the Nutella.
With the extra dough make strips to create a lattice finish. Brush the top lightly with milk and bake in pre heated oven at 350° (180°) for 25-30 minutes or until golden. Let cool then slice. Enjoy!
Notes
*I also make the dough using a food processor, whisk the ingredients together in the food processor cup, then add the egg, yolk and butter and pulse until almost combined, moved to a lightly floured surface and knead gently to completely combine. Wrap and refrigerate.With any extra dough, I made squares and I placed 1 teaspoon of jam in the middle, folded it over, pinched the sides closed and baked in the oven for about 20 minutes at 350° (180°)). The crostata dough can be made in advance and refrigerated, be sure to wrap tightly in plastic wrap. It will keep for up to 3 days in the fridge. The dough can also be frozen. Wrap well in plastic place in a freezer bag and freeze. It will keep for up to 2 months in the freezer. Thaw the dough in the fridge.The pie can be kept at room temperature, covered. A cool area is best. It will keep for 2-3 days. Or if you wish it can be refrigerated for 4-5 days, cover it tightly in plastic wrap.You can either freeze the whole crostata or just the pie dough. Wrap the pie well in plastic wrap and then place in a freezer bag.