Preheat oven to 350°F
Place the butter in a 9x13-inch baking dish and allow it to melt for a few minutes in the oven as it heats. Once melted, remove from oven and set aside.
Meanwhile, drain both jars of peaches, reserving ¼ cup of the peach syrup. Set syrup and peaches aside separately.
In a large bowl, stir the flour, salt, and sugar together. Once mixed, whisk in the milk, vanilla, and ¼ cup syrup from the peaches. Once totally smooth, pour into the baking dish over the melted butter (see note).
Spoon peaches over the batter.
Bake for 1 hour, or until the batter is golden brown and baked up around the peaches. (depending on the oven it could take up to 1 hour 20 minutes)
Allow to cool slightly and serve warm with whipped cream or vanilla ice cream.
