Peach Cobbler with Lemon Topping

Name: Peach Cobbler with Lemon Topping
Ingredients: 6 peaches, cut into thin wedges; 1/4 cup granulated sugar; 1 tablespoon fresh lemon juice (more if your peaches are especially sweet); 1/2 teaspoon vanilla extract; 1 teaspoon cornstarch; A pinch or two of kosher salt, as desired; Freshly grated nutmeg to taste; 1 cup all-purpose flour; 1/2 cup granulated sugar; The zest of one lemon (the one you used for the filling); 1 teaspoon baking powder; 1/2 teaspoon kosher salt; 6 tablespoon unsalted butter, cut into pieces; 1/4 cup boiling water