Preheat the oven to 350°F (177ºC). Butter a 9X13 inch baking dish; set aside.
Make Filling
In a large saucepan, add cherries (9 cups), sugar (1 cup), cornstarch (1/4 cup), and lemon juice (1 tablespoon). Stir until evenly combined.
Cook over medium heat for 8 to 10 minutes, stirring occasionally, until the juices begin to thicken. Remove from the heat and cool for about 10 minutes. If using, stir in lemon zest (2 teaspoons).
Pour the cherry mixture into the prepared baking dish.
Make Topping
Meanwhile, mix all the cake topping ingredients, except the boiling water, to a medium bowl.
Use a pastry blender to cut the butter into the dry ingredients (12 tablespoons) until the mixture looks like a coarse meal.
Pour in the boiling water (1/2 cup) and stir just until the mixture comes together and is just mixed through.
Drop large spoonfuls of the dough topping over the cherries.
Evenly sprinkle the top of the dough with the 3 tablespoons of coarse sugar.
Place the baking dish on a rimmed baking sheet (in case the cobbler bubbles over and drips) and bake for 35-40 minutes or until the topping is golden and baked through and the cherries are tender.
Notes
Let It Cool: This is an important step. It’s not suggested just so you don’t incinerate the inside of your mouth, cooling also allows the juices to thicken, so that it won’t be runny when you serve it.
Add Almond: Almond flavor complements the cherries beautifully. If you’d like to add almond flavor to the filling, I suggest adding 1/2 teaspoon of almond extract to the filling after it has cooled for 10 minutes. Almond extract is powerful, so more than 1/2 teaspoon may ruin the cobbler. While it’s not conventional to add nuts to a cobbler topping, there’s no reason you can’t add chopped almonds to the batter for the topping.
Cutting Butter: Why should you cut butter into your flour, rather than just mixing it all quickly? You want those chunks of unmelted butter to stick around! That’s what will give you a really tender, moist cake at the end.