Preheat the oven to 400 degrees F. Grease a 9-12 inch pie plate or 9x13 inch baking dish with butter. In the bottom of the baking dish, combine the blackberries, honey, lemon juice, vanilla, cornstarch, lavender (if using) and salt. Toss well to combine.In a medium bowl, combine the flour and baking powder. Add the butter and toss together. Add the buttermilk and honey, and mix until just combined, adding more buttermilk if needed. Fold in the cream cheese.Roll the dough out into a 1-inch thick circle or rectangle (depending on your baking dish) and cut into 12-16 biscuits. Place the biscuits over the berries. Brush each biscuit with buttermilk and sprinkle with coarse sugar. Transfer to the oven and bake 40-45 minutes or until the strawberries are bubbling and the biscuits golden brown. Serve warm with a scoop of ice cream, if desired.