1/2 c sugar
pinch of salt
2 T lemon juice
2 T water
1 T gelatin
a prebaked pie crust
Cook the blueberries until they're reduced to three cups, over medium heat, stirring a few times. This will take about half an hour or 45 minutes.
Once that's done, add sugar and salt to the blueberries in the pan. In a small bowl, combine the lemon juice and water, then stir in the gelatin until it starts to thicken a bit.
Stir that into the blueberries, and bring to a simmer and cook for a minute or so. Pour the blueberry mess into your waiting pie crust, and stick the pie in the fridge for a few hours.
This is a good pie to make right at bedtime because then you wake up and it's firmed up enough and you can eat it for breakfast.