To prepare the filling, core and slice the nectarines to appropriate wedges. Heat a tbsp of butter in a large pan and add the nectarines to briefly cook. Scatter a tbsp of sugar over them and remove from the heat. Set aside to cool. Chop the remaining butter into small cubes and mix it with flour and 2tbsp sugar with your hands or a fork until resembling breadcrumbs. Add a tbsp of water at a time, until the dough comes together and could be gathered into a ball.
Heat the oven to 180 C. Divide the dough in half. Flour a rolling pin and work surface, then roll out half of the dough pieces onto a circle larger than size of your pie dish. Transfer onto your dish and scatter the prepared nectarine along with sliced almonds and pinch of salt over the pie base, then evenly pour over 3 tbsp of marmalade. Carefully roll out the second part of the work surface onto 2 mm thickness. Cut the long ribbons out of the dough and arrange them in a lattice poi crust.
Mix the remaining marmalade with milk and brush over the pie with the mixture. Scatter the remaining sugar over and bake for 30-40 min, until the top is golden and the filling is bubbling. Cool briefly and enjoy as a light dessert or fancy breakfast. If desired, dust with confectioners sugar before serving.