Preheat the oven to 400F then slice the butter and place it in a 9x13 inch baking dish and place in the oven while the oven preheats to melt the butter.
5 tbsp butter
In a large bowl, mix the blueberries with the sugar and lemon zest. Stir to combine.
4 cup blueberries, 1/3 cup granulated sugar, 2 tsp lemon zest
In a separate bowl, whisk all-purpose flour, sugar, cornstarch, baking powder, and salt until combined. Add in the milk and vanilla extract and whisk until a batter forms.
1 cup all-purpose flour, 3/4 cup granulated sugar, 1 tbsp cornstarch, 2 tsp baking powder, 1/4 tsp salt, 3/4 cup milk, 1 tsp vanilla extract
Evenly distribute the blueberry mixture in the prepared pan once the butter is melted. Drizzle the batter over the blueberries and bake in the preheated oven for 25-30 minutes. You'll know it's ready when the fruit is bubbly at the edge and a toothpick inserted in the cobbler part comes out clean.
Allow it to cool down a little bit before serving it with some whipped cream, a drizzle of heavy cream, or vanilla ice cream.