Preheat the oven to 375°. To prepare the berries, place in a bowl and toss with the sugar, flour, lemon juice, and lemon zest. Set aside.
To make the dough, mix the flour, salt, sugar and baking powder in a bowl. Cut in the butter until mixture resembles coarse meal. Add the cream and mix lightly, just until the dry ingredients are moistened.
Put the blueberries in a 8-inch square baking dish. Tear clumps of dough off and arrange them over the top of the berries. Bake until the topping is brown and the juices bubble thickly around it, about 25 minutes. Sprinkle top of dough with the course sugar and return to the oven for another 10 to 15 minutes until brown.