Preheat your oven to 375°F (190°C). In a medium bowl, combine blueberries, all-purpose flour, granulated sugar, and lemon zest. Toss gently to coat. Transfer the mixture to an 8 or 9-inch square baking dish, spreading it evenly to form the base layer.

In a large bowl, whisk together flour, salt, granulated sugar, and baking powder. Add cold butter and use a pastry blender or two knives to cut the butter into the flour mixture until it resembles coarse crumbs. Pour in half and half and stir gently until just moistened. Avoid overmixing.

Drop spoonfuls of the cobbler dough over the blueberry layer in the baking dish, leaving small gaps to allow the blueberries to bubble through during baking. Place the dish in the preheated oven and bake for 35-40 minutes, or until the topping is golden brown and the blueberries are thick and bubbling around the edges. Test the topping with a toothpick; it should come out clean.

Let the cobbler cool for about 10 minutes to allow the juices to thicken further. Serve warm, optionally garnished with a sprinkle of powdered sugar or a scoop of vanilla ice cream.