Preheat your oven to 350°F (175°C). Grease a 9x9-inch baking dish.
Mix the dry ingredients. In a large bowl, whisk together flour, baking powder, salt, cinnamon, and brown sugar.
Add the wet ingredients. Stir in milk, melted butter, and vanilla extract until smooth. The batter will be thick but spreadable.
Spread the batter. Pour the mixture into the prepared baking dish, smoothing it out evenly.
Make the topping. In a small bowl, combine brown sugar, salt, and cinnamon. Sprinkle this evenly over the batter.
Pour hot water. Slowly pour hot water over the top without stirring—this is the secret to creating that gooey cobbler sauce.
Bake. Place in the oven and bake for 35–40 minutes until the top is golden and the cobbler is bubbling around the edges.
Cool slightly before serving. The sauce thickens as it rests. Serve warm with a scoop of vanilla ice cream or whipped cream.
