Preheat the oven to 425°F. Line a 9" pie plate with pie pastry ensuring that the pastry sits firmly in the bottom corners and also extends to the entire edge of the pie plate.
To a large bowl, add the raspberries, sugar, flour, lemon juice and cardamom. Mix well with a spoon to coat.
Add the raspberry filling evenly to the pastry lined plate. Dot with the cold butter.
Lay the second layer of pie pastry on top of the raspberry filling and seal by pinching with your fingers or with a fork. Trim off any extra pastry from the edges with a sharp knife.
In a small bowl, whisk the egg and milk together. Using a basting brush, baste the top of the pie with the egg wash and then sprinkle with coarse sugar if you wish.
Place the pie in the oven and then slide a lined baking sheet on the shelf below the pie to catch any filling that may spill over while baking. Bake for 15 minutes.
Lower the temperature to 375°F and continue baking for an additional 35-40 minutes. The pie is done when the crust is golden and the filling is starting to bubble.
Remove the pie from the oven and let it cool for 2 hours before serving.
Notes
Assembling in Advance:Baking within an hour or two of assembling is fine. Any longer than that in the fridge and the sugar will pull the juices out of the berries, leaving you with a weeping pie.To prep ahead, assemble the pie, wrap it tightly in plastic wrap right in the pie plate, and freeze. An unbaked fruit pie will keep in the freezer for up to 4 months.To bake from frozen, add it to the oven straight from the freezer. Add an extra 5 minutes at 425°F and another 10 to 15 minutes at 375°F.Storage:Store any leftovers on the counter tightly sealed for up to 3 days or freeze by double wrapping. This pie can freeze for up to 4 months. Thaw in the fridge before serving.