Preheat oven to 400 degrees.
Combine sugar and cornstarch in a bowl. Blend in blueberries and lemon juice. Arrange into ungreased 2-quart casserole. Set aside.
Combine egg, melted butter, and cream in a bowl; Whisk and set aside.
Biscuit topping:
Combine in a bowl, flour, sugar, and baking powder. Make a well in center of dry ingredients, and put egg mixture into well. Mix dry and wet ingredients and work dough until just mixed together. Drop dough by spoonfuls onto fruit, spreading evenly over the surface. Bake 25 to 30 minutes or until biscuit topping is golden brown. Serve warm with ice cream.