Preheat oven to 375°F. Lightly butter a small baking dish (like a 5x7, or 6-inch cast-iron skillet, or two ramekins).
In a bowl, toss sliced peaches with sugar, vanilla, cinnamon, and lemon juice. Let them sit while you make the topping to get those juices flowing.
In a separate bowl, whisk together flour, cornmeal, sugar, baking powder, and salt. Cut in the cold butter with a fork or your fingers until the mixture looks crumbly. Stir in just enough buttermilk to bring it together into a thick, spoonable dough, like biscuit dough.
Spoon the peach mixture into your prepared dish. Dollop the topping evenly over the peaches—don’t worry about perfection; the rustic look is part of the charm. Sprinkle the top with a pinch of cane turbinado or raw sugar for a bit of sparkle and extra crunch.
Bake for 25–30 minutes, or until the topping is golden and the peach filling is bubbling around the edges.
Cool slightly and serve warm—with vanilla ice cream, whipped cream, or just a spoon and a smile.