Easiest-Ever Blueberry Biscuit Cobbler

Ingredients

• 5 cups fresh blueberries
• ⅓ cup granulated sugar
• Zest of one lemon
• 1 tablespoon all-purpose flour
• Pinch of kosher salt
• Topping
• ¼ cup granulated sugar
• 2 cups all-purpose flour, plus more for dusting
• 1 tablespoon baking soda
• 1 teaspoon kosher salt
• ½ cup (1 stick) unsalted butter, cold, cut into cubes
• 1⅓ cups heavy cream, cold
• 2 tablespoons unsalted butter, melted
• Demerara sugar, to garnish