Add strawberries, sugar, and vanilla to the pan. Toss to fully mix. Bake in the preheated oven for 15 minutes.
In a large food processor, combine flour, sugar, baking powder, and salt. Pulse to mix. Add the butter. Pulse until batter forms coarse crumbs. Can also use a pastry cutter in place of a food processor.
Whisk together vanilla and buttermilk. Add to the flour mixture. Pulse in the food processor or fold into flour mixture. Do not overwork. The dough should be fully moistened and crumbly when it is done.
Remove the strawberries from the oven. Drop the topping mixture by spoonfuls over the strawberries making sure to leave some space for steam to escape. Sprinkle coarse sugar over the top.