Preheat the oven to 375° F
Make the pie crust: In a mixing bowl combine the flour and salt. Cut the lard into cubes and add to the flour. Using a pastry blender, cut the lard into the flour until it resembles pea-sized pebbles. Add 5 tablespoons of ice water and blend into the flour with a fork. Add another tablespoon or more if needed to pull the dough together. Gather the dough together and press into a ball. Wrap with cling film and chill for about an hour.
Make the filling: Wash and chop the rhubarb into small pieces. In a mixing bowl add the eggs and milk and whisk together. Add the sugar, flour, salt, and nutmeg and whisk until it forms a smooth batter. Stir in the chopped rhubarb and set aside.
Make the crumble topping: Combine the flour and brown sugar in a mixing bowl and blend together. Cut the butter into cubes and add to the flour. Using a pastry blender, cut the butter into the flour until it resembles pea-sized pebbles.
Roll out the pie crust: On a lightly floured surface roll out the pastry into a circle about 13 inches in diameter. Transfer the dough to a 9 inch glass pie plate by folding the dough in half, placing in the pie plate and then unfolding the dough. Gently lift the edges of the dough to line the sides of the pie plate without stretching the dough. Trim the excess dough around the edges leaving a ½ inch edge. Crimp the edge decoratively.
Assemble and bake the pie: Pour the rhubarb filling into the pie crust. Sprinkle the crumble topping evenly over the pie filling. Bake at 375° F for 50 to 60 minutes. Check the pie near the end of the baking time, if the topping is getting too brown then loosely cover the pie with a piece of foil. The pie is done when the filling is puffed and the centre no longer jiggles when shaken. Let cool for at least an hour before cutting.