In a large saucepan or non-stick skillet, whisk together the sugar and cornstarch, then add in the lemon juice, water and berries.  Bring this mix to a boil while stirring regularly and allow it to simmer for about 5 minutes – it will thicken quite quickly, but definitely boil for the allotted time so that your pie ends up with a lovely/cuttable consistency.  Remove the pot from the heat and if you have time, allow it to come to room temperature.

Roll out your pastry as you would and fit it into the pie plate with a bit extra hanging over the edges.  Have your second sheet of pastry ready to go before pouring the filling into the prepared pie plate, especially if the filling is still warm!  Drop the butter in small blobs across the top of the filling and then cover it with the second sheet of pastry.  Dampen, trim and flute the edges and then cut a couple of air vents into the top.  Bake at 450 for 10 minutes, then cover the edges with foil, or an ‘edge protector’, and turn the heat down to 350 and bake for another 35-40 minutes.

Allowing the pie to rest for a couple of hours will also make it easier to cut slices!