Preheat the oven to 375 degrees F. and spray an 8x8 baking dish with nonstick cooking spray.
Place the diced peaches in a bowl and toss with 1 tablespoon of Splenda. Spread the peaches evenly in the bottom of the baking dish.
In a separate bowl, combine the self-rising flour, skim milk, vanilla extract, and remaining 1/2 cup Splenda.
Pour the batter evenly over the peaches. Dot the top with small pieces of butter.
Bake for 45 minutes, or until the topping is golden brown and cooked through.
Allow the cobbler to cool for several minutes before serving.