Position rack in center of oven and preheat to 350°F.
Add the sliced peaches to a pot or large saucepan. Add sugar and water; stir well to dissolve. Bring to a boil, reduce to a simmer, and cook for 5 minutes, stirring occasionally. Remove from the heat and set aside.
While the peaches are simmering, add the sliced butter to the bottom of a 9- by 13-inch glass or ceramic baking dish. Place in the oven until melted.
While the butter is melting, make the batter. Use a whisk to stir together the flour, sugar, baking powder, and salt in a large bowl until well-combined. Slowly mix in the milk, and then rapidly whisk until smooth.
Use oven mitts to remove the baking dish from the oven, tilting the dish so that the butter evenly coats the bottom. Slowly and evenly pour the batter into the dish, which will cause the butter to rise up against the sides. Use a big spoon to carefully scatter the peaches onto the batter and then evenly pour over all of the syrup without stirring. Sprinkle the top of the Peach Cobbler with as much cinnamon as you prefer (if using).
Bake for 35 to 45 minutes or until the batter has puffed up and the edges are golden (you can also use a toothpick to test a clump of batter towards the center of the baking dish). Serve warm with vanilla ice cream.
Notes
6 to 7 average-sized peaches should yield 2 pounds (or 4 cups sliced), but you may need more or less peaches depending on their size.
Ripe, sweet peaches probably only need to be simmered with ½ cup added sugar. However, if you’re using less ripe/less sweet peaches (or frozen peaches), you may want to add ¾ cup or 1 cup of sugar to the peaches.
Since you layer the components in the baking dish without stirring them together, Easy Peach Cobbler may look strange and liquidy when you put it into the oven. However, as it bakes, the melted butter and peach syrup will be absorbed and the batter will rise up and around the peaches.
The cinnamon is optional but recommended. I like to add a generous amount myself.
In my oven, Easy Peach Cobbler is perfectly baked at 40 to 41 minutes. Your particular oven may require slightly more or less time.
See info box in post for directions on "Substituting Frozen or Canned Peaches" in this recipe.