1. For the filling: Position a rack in the center of the oven and preheat the oven to 375 degrees F. In a medium bowl, stir together the sugar, flour, and nutmeg. Gradually whisk in 1/4 cup water and lemon juice to make a smooth mixture. Add the fruit and toss gently to coat evenly. Transfer to a shallow, 2-quart heatproof baking or gratin dish and dot with butter. Set aside.

2. To make the biscuit: In a large bowl, stir together the flour, sugar, baking powder, and 1/2 teaspoon fine salt. Work in the butter with your fingertips until the texture resembles coarse meal. Add the milk, vanilla, and lemon zest to the dry ingredients and stir just until moistened to make wet, slightly lumpy dough. Do not over mix.

3. Put the baking dish on the stovetop over a medium-low heat, and stir the fruit mixture gently until it simmers. Reduce heat to low and cook until thickened, about 2 minute. Remove from the heat.

4. Drop large spoonfuls of dough onto the top of the peaches, randomly spacing mounds of dough and leaving some uncovered areas, to give a "cobbled" look. Spread the dough to an even thickness and sprinkle dough with sugar, if desired.

5. Bake the cobbler until the biscuit is lightly browned about 45 minutes. Let the cobbler set up at room temperature for 20 to 30 minutes before serving. Serve warm or at room temperature.