Prepare your peaches by blanching, peeling, and slicing them. Set aside.

Preheat the oven to 375F. Place the butter in your 9×13 baking dish, then transfer into the oven to heat until the butter is melted.

Add the sliced peaches to a skillet with the brown sugar and cook on medium heat until the sugar has dissolved and the peaches and liquid have reduced. (about 15–20 minutes)

Once the peaches and liquid have reduced, add the spices and salt to your cornstarch in a separate bowl, mix well.

Add the cornstarch and spice mixture to the peaches, then bring everything back to a high simmer until the peach filling begins to thicken.

Remove the peaches from the heat, then add the lemon juice and vanilla extract. Mix well.

Combine the flour, salt, sugar, and baking powder in a large bowl then whisk together. Add the milk and mix until just combined.

Remove the baking dish with the melted butter from the oven, then pour the batter over the butter. (do not mix together).

Spread the batter to the edges, then spoon the peach filling over the batter. Be sure to leave spaces in between the peach filling, so the batter can rise to the top.

Bake at 375F for 35–40 minutes, or until the top is light golden brown.