Preheat your oven to 350°F and slice the butter into pieces. Place the butter in a 9x13 inch baking dish and place it in the oven to melt while it preheats.
In a bowl, combine the blueberries, sugar, and zest, and stir to combine.
In another bowl, mix together the flour, sugar, baking powder, and salt. Stir in the milk until just combined.
Once the butter is melted, remove the baking dish from the oven. Pour the blueberries over the melted butter, then drizzle the batter over the top. Sprinkle with cinnamon.
Bake at 350°F for about 35-40 minutes, or until lightly golden on top.
Serve the cobbler warm from the oven, optionally with a scoop of vanilla ice cream.