Place the 5 tablespoons of butter for the cobbler topping in the freezer for at least 30 minutes.
Preheat oven to 350° F. Grease an 8x8 or 9x9-inch baking dish.
Make the cherry cobbler filling: In a large bowl, combine the cherries, sugar, cornstarch and vanilla extract. Use a rubber spatula to mix gently until combined. Set aside while you prepare the topping.
Make the topping: In a large mixing bowl, whisk together the flour, sugar, baking powder, cinnamon and salt until well combined. Use a box grater to grate the frozen butter, then add it to the dry ingredients in the bowl. Stir in the grated butter with a fork.
In a liquid measuring cup or bowl, stir together the buttermilk and vanilla. Pour the buttermilk mixture into the dry ingredients and use a fork to mix until the dough comes together. The dough will be somewhat dry, but it should come together after some mixing.
Stir the cherry mixture again to make sure everything is well combined. Pour the cherries and all juices from the bowl into the prepared baking dish. Divide the cobbler dough into 9 portions. Flatten each portion slightly so that it is about ¾-inch thick and place on top of the cherry filling. The dough pieces do not need to be perfectly round; the cobbler will have a somewhat rustic look to it. Lightly sprinkle the top with sugar, if desired.
Bake for 40-50 minutes, until the filling is very bubbly and the topping is golden brown and cooked through.
Let cobbler cool for at least 15 minutes before serving.