In a large sauce pan or Dutch oven, combine cherries and water. Cover and cook over medium heat until cherries release their juice, stirring frequently, 10 to 15 minutes. In a small bowl, combine sugar and cornstarch and mix to combine. Increase the heat under the cherries to medium high and bring liquid to a simmer. Add in sugar mixture, and stir thoroughly to combine. Stirring continuously until mixture thickens, 3 to 5 minutes. Remove from heat. Stir in almond and vanilla extract and 1/4-cup of the slivered almonds.
Preheat oven to 350 F and butter a 3 quart baking dish. Pour cooled filling into prepared baking dish.
In a large mixing bowl sift together flour, sugar, baking powder, and salt. Using a pastry blender or forks, cut in cold butter until the mixture looks like coarse crumbs. Add half-and-half and stir until just combined. Be careful not to over mix dough. Drop by heaping spoonful onto filling, leaving some space between dough drops. Note: The drop biscuit dough will rise and expand, the closer together you place the dough drops the less filling will peak through the finished cobbler. Sprinkle remaining slivered almonds over cobbler. Sprinkle turbinado sugar over the drop biscuits, if desired.
Bake in preheated oven for 35 to 45 minutes until drop biscuits are golden brown and filling is bubbling around the edges. Remove from oven and let cool 30 minutes before serving.