1/2 cup unsalted butter divided, cut into small pieces
Preheat oven to 400 degrees.
In a large bowl, combine peaches, vanilla and 1/3 cup maple syrup if using. Set aside.
In a separate large bowl, combine oats, salt and cinnamon. Cut in 1/4 cup of butter using your fingers until the mixture resembles coarse breadcrumbs. The oats may cause large pieces to stick together, and that is fine.
Add the peaches to the oats and mix to combine well. Taste the mixture and add additional maple syrup if desired.
Pour into a 9×13 baking dish and dot the top with the remaining 1/4 cup of butter.
Cover with aluminum foil and bake for 45-60 minutes, until the peaches are soft and the oats have browned.