Peel the sweet potatoes and then cut in half lengthwise then slice into half-moon shapes, about 1/2-inch thick.
Place the cut sweet potatoes into a pot large enough to hold them, along with the water, granulated sugar, brown sugar, spices, salt and vanilla extract.
Bring the pot to a boil then turn the heat down to low and simmer until the sweet potatoes are tender but firm.
Lightly grease a 9×13 baking dish or a large cast-iron skillet. Once the potatoes are done, transfer them with a slotted spoon to the baking dish, leaving the liquid in the pot.
Turn the heat on the pot to high, and boil the liquid until it’s reduced by 1/2 and slightly thickened, about 15-20 minutes, while occasionally stirring. You should have about 1 cup.
Preheat oven to 375F.
In another bowl, make the dough by mixing the flour, cinnamon, and brown sugar together.
Cut the butter into the flour mixture with a pastry blender or two large dinner forks. It doesn’t have to be perfect!
Slowly pour the milk into the flour mixture while stirring. Stir until the mixture is combined. The dough will be crumbly and slightly sticky. Only use as much milk as you need to get it to the right texture.
Place the dough on a lightly floured surface. Knead it a couple of times and then it out until it’s roughly a 9×13 inch rectangle or a 10-inch round circle, depending on whether you’re baking the cobbler in a baking dish or skillet.
Evenly pour over the sweet potatoes the syrup and then place on top of the sweet potatoes the cobbler dough.
Sprinkle over the dough the remaining 1 tablespoon of granulated sugar, and then cut into the dough several slits so steam can release.
Bake uncovered for 30-35 minutes, or until the top is golden brown. Allow to cool for 20 minutes, then serve. Serve each slice topped with whipped cream or vanilla ice cream.