In a medium saucepan, combine the sliced peaches (4 cups) with the brown sugar (1/2 cup) and a small pinch of salt and and cook on medium for just a few minutes, until the sugar is dissolved and the peaches are very juicy.
Add the melted butter (8 tablespoons) to the bottom of a 9x13 baking dish. (Tip: You can melt it separately and pour it in, or just stick the whole pan in the microwave or in the oven to melt the butter directly in it.)
In a large bowl, mix together the flour (1 cup), the baking powder (2 teaspoons), and the sugar (3/4 cup). Stir in the milk (3/4 cup) until just combined. Pour on top of the melted butter in the baking dish, and smooth it out as best you can with a wooden spoon or spatula (it's OK if it's not perfect!).
Pour the peach mixture evenly on top of the flour mixture.
Sprinkle evenly with the ground cinnamon (1 teaspoon) and the turbinado sugar (1/4 cup).
Bake for 30-40 minutes, or until browned on top. If you like, you can broil it for the last 2-3 minutes to form an extra-crispy and browned caramelized sugared layer on top. Serve warm with vanilla ice cream or whipped cream, if desired.
To use canned peaches: Skip melting the sugar and peaches together and instead pour the canned peaches including the syrup on top of the butter and batter mixture in the baking dish.
Make it healthier: Use 5 tablespoons of butter instead of 8 and reduce sugar to 1/2 cup. You can also use honey or maple syrup instead of the brown sugar with the peaches.
Don't have turbinado sugar? No problem-just substitute a little more white or brown sugar for it.
If using unsalted butter, make sure to add a pinch of salt to the batter.
The provided nutrition information does not include any added sodium from seasoning to taste, any optional ingredients, and it does not take brands into account. Feel free to calculate it yourself using this calculator or by adding the recipe to Yummly.